Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: jzearfoss on April 10, 2019, 19:22:34
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In the throes of reinstalling engine and throttle linkage on my 1968 280SL (LHD, automatic).
My problem is with the pivot arm mounted on the right-hand side of the block below the intake and exhaust manifolds. The Push Rod (part # 113 300 00 15) from the throttle Control Shaft (part # 113 300 05 20) extends beyond the ball on the upper arm of the pivot.
The socket on the end of the Push Rod does have some adjustability but not enough to connect to the ball on the upper arm of the pivot. I do not have photo of this connection from when I pulled the engine so I do not know what the connection is supposed to look like.
I have searched through the BBB and the Linkage Tour here on the Pagoda site and have come up empty for any image or diagram for this connection or an answer as to why the Push Rod and pivot arm geometry is off. I know the mounting plate (part # 127 072 1401) is mounted correctly. My best guess is that there is another linkage piece from the Push Rod back to the pivot arm. It would have to be a ball on one end and a socket on the other. I can not imagine that I would have lost a part like this but, well you know, sometimes we just screw up.
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Would appreciate any help on solving this problem
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Here is a pic of my connection.
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That is the only picture I could find... it is RHD...
The elbow of that lever attached to the cross-shaft seems to be going further backwards, almost under the cross-member. I am not sure if this is helping.
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Thanks mrfatboy and Pawel66. I sure do appreciate the photos. The one from mrfatboy is exactly like my before picture when I took the motor out. The shaft that the pivot arm rides on is almost directly above the upper right-hand bolt for the engine mount. So I am sure I have that installed correctly. It appears then that the Push Rod is to long. This is the only one I have from disassembly of the car so it has to be what was originally on there.
Does anyone have any specs on what the length of the Push Rod is?
The Throttle Control shaft (also referred to as the accelerator shaft)and the elbow to which the Push Rod connects is a single welded component so there is no adjustability there.
Any other theories or suggestion on what may be my problem will be happily accepted.
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I have the cylinder head and manifolds off and should be able to show a picture of the connection. I will take one tomorrow.
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The horizontal rod on my car measures approx. 350mm from center to center. My wife had to help😁
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Mine seems longer - estimated 380mm center to center. The rear looped end is directly below injector 6 and the front socket end sits approximately where yours (jzearfoss) is now, i.e. near the 4 o'clock bolt on the cover plate. But my rod bracket is attached to the 4 and 6 o'clock bolts on the cover plate whereas your is attached between 6 and 8 o'clock, so the arrangement on my LHD 230SL 4-speed is probably irrelevant for your LHD 280 auto. I guess your cover plate and bracket should look like mrfatboy's, which they do. Also not sure this is helping :)
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In found another picture for you. Maybe it will help.
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Does these help? The length was 345 mm in my car.
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Is it possible this is not your original rod? Could it have been swapped at the platers? Unlikely I know.
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Thanks everyone for the photos and measured lengths of the Push Rod. I will be doing some disassembly today and check lengths again.
To DaveB. I did not farm out any plating so this is the original Push Rod that came off my engine. Also DaveB I checked my photo for the mounting plate orientation and if you look you can see that the part # cast into the plate is horizontal, so I am confident that the mounting plate is bolted on correctly. Good observation though.
I have one thing I need to check. After looking again at the Linkage Tour I see on p.9 there is a diagram titled Pedal Linkage and in the diagram I see that Item 1 (Pedal lever) has the tang where the gas pedal contacts the pedal lever is facing to the left. Mine is facing to the right. If my suspicions are right this may be my fix. It appears that it is possible to install the pedal lever 180 degrees off. Will confess my sin if this proves to be my salvation.
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It looks like you have your answer already, but here are some pictures and measurements from my 1971 280SL, as promised.
Length of rod from rear pivot center to center of ball joint is almost exactly 320mm.
And of course, my engine compartment and the hardware therein doesn't look near as nice as some of these others... 8)
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I am examining the various throttle linkage photos and comparing them to the photo you posted with your original query and am concerned that the problem may not lie with your push rod, but rather with the throttle bar on the firewall to which it is attached. The end that engages the "loop" in your pushrod seems to be quite a bit farther forward along the side of the block in your photo than in any of the photos posted by others. Is it just possible that the other end of the throttle bar may be hung up on something behind the foot pedal, such that it is positioned in a "foot to the floor, wide open" condition?
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To MikeHuges - I think you have it right. The regulating shaft is not rotating far enough back towards the fire wall.
I must have not had enough caffeine in my coffee this morning. The pedal lever is in correctly but I can see that the elliptical hole on the inside of the fire wall under the dash (where the pedal lever enters from the engine compartment) is restricting the travel of the pedal lever and therefore restricting the degree of rotation I can get on the regulating shaft. I have about 30 mm of travel I can gain before the "loop" (as Mike calls it) hits the firewall.
I am going to get my dremel out and trim the top of that elliptical hole to see if I can get the pedal lever more travel and therefore increase the rotation of the regulating shaft.
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Why dremel it out?
It was all in good position before taking the motor out. Right?
Maybe the pas pedal rod itself is in wrong position.
Did you check the two aluminum clips that hold the pedal rod to the firewall?
Rod should be below the aluminum clips(i.e. the two 8mm bolts should be on top side.
Just imagining, as there is no picture of this.
Walter
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Actually, as Walter says, feels like you might have fitted, at least the aluminum clip on the driver's side, upside down perhaps...
Bear in mind you also have a grommet there - you need quite a lot of clearance between the gas pedal lever and the edge of the hole in the firewall.
Or: you fitted the gas pedal lever on the shaft at a wrong angle. I do not remember exactly how it looks there now, but perhaps you fitted the gas pedal lever "pointing too high" towards the firewall. The gas pedal lever slides onto the shaft and it is secured by a screw to the lever where return spring is attached. Maybe you had too much play/slack in the screw hole in that spring lever?
Note the upper length of the lever on the passenger side is pretty much "upright" or parallel to cross member at gas pedal idle position.
As per Walter's advise, I would put dremel aside.
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Thanks Waltklatt - You are right, all was in good position and working before removing the engine. That is why I am so perplexed as to why things are not fitting as I expected.
The two aluminum fittings that hold the regulating shaft are in the correct position. On the passenger side the two phillips head bolts are on the top side of the regulating shaft and on the drivers side the two phillips head bolts are under side of the regulating shaft. They have to go on this way as it is the only geometry that permits the regulating shaft to pass behind the valve cover.
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To all who are responding to my query on this problem I do appreciate any and all ideas and suggestions as to how to get things back to square one. May I ask one consideration.
When I describe the parts in this particular situation I am using the terminology in the diagram on p. 9 of the Linkage Tour titled Pedal Linkage. That diagram comes directly from the BBB at 30-1/1. I know that it is not uncommon for the same component to be referenced by different names.
In fact in the diagram on page 48 of the MB Publication 10202 (Mercedes-Benz TYPE 250 SL - 280 SL / Chassis and Body Spare Parts List Edition C/ as per Jan. 1972 / which supersedes Edition B of Jan. 1968), every component has a different reference number than what you see in the diagram in the Linkage Tour p.9, and they appear to be the same diagram but if you look close will see minor differences and different terminology for the same component.
I am pretty sure most everybody knows that MB was constantly making changes to components not only between production years but even during production runs. ( SEE Pagoda Notes Vol.9 No.4 thru Vol. 10 No.4). So there are ample opportunities for confusion to arise.
Please bear with me as I trudge along on this problem. I am sure a solution will emerge and all will be right in Pagoda World.
Thanks again.
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What I was trying to say in my post was that (referring to Technical Manual) you might have got wrong the adjustment on bolt no. 51. Perhaps if you have too much slack there in the hole in the spring lever and the bolt ends up in maximum down position in the spring lever hole, the gas pedal lever may be high enough at the firewall to collide with the edge of the hole in the firewall.
Theory easy to eliminate.
By the way: I have not seen before this "additional" lever with the screw in it... but perhaps I have not seen a lot.
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I am examining the various throttle linkage photos and comparing them to the photo you posted with your original query and am concerned that the problem may not lie with your push rod, but rather with the throttle bar on the firewall to which it is attached. The end that engages the "loop" in your pushrod seems to be quite a bit farther forward along the side of the block in your photo than in any of the photos posted by others.
That is definitely the reason for the problem. What the cause is, I do not know.
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To Pawel66 - I have adjusted bolt #51 (as per Fig. 30-1/1) to both extents of the slotted opening in the tang where the bolt goes through and then threads into the pedal lever. It does not give me enough additional rotation of the Regulating shaft to make up the distance I need to get the Push rod connected to the pivot.
Looking at MikeSimon's comment I have to agree with him in that the push rod is not back as far as it should be against the firewall. That is the reason for the problem, but I am still searching for the cause.
Attached are a couple of new photos of the Regulating shaft: one is of the driver's side and shows everything installed.
Pawel66 - the tang with the screw that you mention is what actuates a micro-switch, which is wired to the fuel shut-off solenoid on the fuel injection Pump (FIP). My 280 has an automatic transmission and on U.S. imports the FIP has both a starting solenoid (the upper one) and a fuel shut-off solenoid ( the lower one) on the rear of the FIP. There is a good diagram of this configuration in the Haynes Manual (Ch.3) on p.77(Fig. 3.76). There is also a diagram of the wiring for the micro-switch (Fig. 3.77).
Hey Pawel66 - where is the diagram you posted (control.JPG) from. The component numbers do not match either the Linkage Tour diagram or the Publication 10202 diagram. Just wondering?
To all - just as a point of interest. If you look at the diagram I posted from Publication 10202 you will see in the lower right-hand corner a representation of the Regulating shaft for a right-hand drive vehicle.
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Tank you - understand what the additional lever is for - I indeed have not seen enough, let's not side track your thread.
Picture - SLS, I just had it at hand. Again, let's not pollute your thread and stick to your picture of the assembly.
I just went to the garrage - my assembly looks like yours.
If you say the issue is that the gas pedal lever gets stuck against the upper edge of the hole in the firewall it goes through - I am afraid I am short of ideas... sorry.
Other than - losen all the screws of the entire assembly, then try to fit it again, then tighten carefully watching for how elements rest in place. Mybe shims under the driver's side aluminium holder will give you some space? I also see paint scratches on top of the lever on passenger's side - maybe somthing is going on there.
Also - sorry for my ignorance - I do not remember the role of part no. 14 on your diagram, the cage nut, (do not remember now how it was on my car when I dissassembled the shaft). Did you look into that?
sorry..
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.../...By the way: I have not seen before this "additional" lever with the screw in it.../...
It is only to be found on US 280 SL:s. Has to do with emission control system (additional relays for shutoff, just as jzearfoss writes)
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Is it possible that the silver bracket on the firewall that holds the electric switch is installed upside down? If that switch were sitting lower down the shaft could rotate a little more before the screw meets the switch.
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Here are some more reference pictures that might help.
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The switch bracket on my 280SL appears to be a bit different from mrfatboy's the way it is attached to the firewall. If I remember correctly it was right-left adjustable but not up-down. Perhaps Joe A. remembers?
After the engine overhaul he did not reinstall the switch because it provides only a tiny fuel consumption improvement and can cause only problems.
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Regarding the gas pedal arm hitting the hole in the firewall: Loosen the gas pedal shaft fixing bolt on the throttle shaft lever and adjust the angle of the pedal shaft. The slot in the lever that the bolt tightens to is elongated for adjustment.
In one of the photos mrfatboy posted you can clearly see the elongated slot. You can see his pedal arm is adjusted such that the pinch bolt is at or near the lower extreme of the elongated slot. It appears that your pinch bolt is at the upper extreme of the elongated slot.
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To mrfatboy - Thanks for the photos. Should be helpful as future reference for others as they tackle their rebuilds. For me they confirm that I have the mounting hardware correct but I am still unsuccessful in solving my geometry problem.
to Mike Hughes - I have done as you suggest with the bolt that holds the regulating shaft to the pedal lever. It buys me a little but not enough to give me what I need at the pivot where the regulating rod (push rod) connects.
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At this point I would suggest to disconnect the linkage (attached to pedal) on the left side of the firewall.
Connect the horizontal rod to the pivot bracket on the right side of the engine.
From there back track which might help you find the problem. It will help you find where things like to be.
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I would agree. Just remove the pinch bolt for the pedal arm. If you still can't get the pivot arm to drop down enough to attach the push rod at both ends, then work back along the throttle shaft that crosses behind the engine to see what is hanging it up. I'm hoping that it is just the microswitch on the firewall and that flipping over the bracket and reinstalling it so that the switch sits a little lower does the trick.
I'm also hoping that it is not that somehow the pivot arm was stepped on or otherwise bent, twisted or otherwise realigned with the throttle shaft while it was off the car. That's the sort of thing one wouldn't notice until later - like now! The only reason why I even bring that up as a possibility is that it looks in your one photo like the arm with the adjustment screw that contacts the microswitch may have been bent already and I would assume that significant force would have been involved for that to have happened.
Can anyone comment on how that pivot arm is attached to the cross throttle shaft? Is it tack welded or brazed, or is it pinned?
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Here we go - day 4.
Thanks Mike for the input. Every connection has been apart and reassembled several times now, in both directions - from the pedal lever forward - from the regulating rod back. No improvement. And lowering the micro-switch bracket is ineffectual.
Mike - regarding your idea that the regulating shaft or regulating rod or the lever arm with the slotted hole may have been bent, twisted or otherwise realigned while off the car. I am inclined to come to the conclusion that the evidence does not support that theory. The regulating shaft is solid steel (dia.=5/8"), regulating rod is solid steel (dis. =1/2") and the slotted hole lever is solid steel (1/8" thick = 11 ga.). Is was stored in a typical 64 qt. plastic tub on a shelf and did not come off the shelf until I started the reassembly.
The regulating rod and the slotted hole lever are welded on the regulating shaft so there was no possibility of rotational slippage. Yes the micro-switch lever arm is twisted a bit in a lateral direction but it was like that before the regulating shaft was removed.
New question:
Can anyone tell me the distance between the back of the valve cover and the fire wall?
It must be enough so that the valve cover can be removed while the engine is still in the car. It would have to be far enough forward to clear the welded bracket that holds the hood release mechanism. I can not remove my valve cover the way the engine currently sits in the car. It will not clear the welded bracket.
See what I am getting at here. My guess (at this point anyway) is that the engine is not far enough forward for the regulating rod to fit correctly with the pivot on the engine block.
If I put the car up on jack stands and have the wheels clear the floor and I unbolt the two bar leaf springs that connect the crossmember to the front of the frame then the whole crossmember/front suspension assembly is free to swing (forward) as it hangs from the flexible mountings that bolt the crossmember to the frame. Every bushing and flexible mount has been replaced with new rubber so I am sure things have tightened up a bit.
There are other connections points that need to be addressed as well: the steering idler, the steering damper, as well at the pitman arm, but I am willing to start messing around with this possibility.
Any thoughts or suggestions out there? jz
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Here ya go. Measurements are close. The green measurement would be from the top plane and back of the valve cover across to the bracket on the firewall.
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Hey mrfatboy - if you were to remove you valve cover would you then be able to remove the regulating shaft from off of the firewall?
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Yes. I can even remove it with the valve cover on. It would be a tight squeeze though. I probably would end up pulling it through as not to scratch paint.
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jzearfoss, if you cannot remove the valve cover because it cannot clear the hood lock assembly - it often means your transmission mount rests too low. In the regular usage of the car it is an indicator that you should look at/replace your rubber mount in the back there.
It does not have to mean your engine is somehow too far back.
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To Pawell66 - I have new rubber there too. I have the tranny jacked up on a wheeled jack to the the level it would sit when installed and connected to the driveshaft. The bit of tilt (and resulting angling back of the valve cover) that might have resulted from the back of the tranny being to low is a non-issue. Good catch though. jz
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I am keeping my fingers crossed you find solution to this topic quickly.
I wish i could be of more help.
I am not experienced enough obviously to figure out how come your engine may be too far back.
But every time I go through pictures, i have an impression that the lever attached to cross shaft on the passenger side is bent downwards in your case less then e.g. mine or the other ones in the pictures.
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Can you post a picture at the same angle I did in post #30? What are your measurements? Maybe even more pictures might help us see what is going on.
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You have the pictures from mrfatboy and from me of that lever at 90deg angle (more or less). The lever is "upright" along the firewall. Is it the same in your car? If not - is it caused by the gas pedal lever lack of clearance in the firewall hole or something else?
If it is the lack of clearance on the hole - I am back to square 1 with no ideas.
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Been out of town for a couple of days. Back now so will snap a few photos as requested and get them posted later today.
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Here are 4 photos of the regulating shaft that may clear up what is lacking in previous posts:
Photo1 -this shows the regulating shaft on the passenger side and its clearance from the firewall when it is NOT connected to the pedal lever and bolt #51 is removed. The clearance from the firewall is approx. 3-5 mm. The gas pedal and pedal lever are in the position of being at full idle and the result is that the threaded hole where bolt #51 is supposed to attach to the pedal lever is in such a position that the bolt can not be secured.
Photo2 - this shows the regulating shaft on the drivers side where it is would connect to the pedal lever and as noted above - bolt #51 can not be secured to the pedal lever.
Photo3 - this shows the regulating shaft on the passenger side and its clearance from the firewall when it connects to the pedal lever and bolt #51 is secured at the top of the slotted opening .The clearance from the firewall is approx. 30mm. When in this position the gas pedal and pedal lever are in the position of being at full idle and bolt #51 can be connected to the pedal lever.
Photo4 - this shows the regulating shaft on the drivers side where it connects to the pedal lever and as noted above - bolt #51 is secured at the top of the slotted opening.
Hope these help. jz
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And in the "almost full idle" position the gas pedal lever gets stuck against the upper edge of the hole in the firewall and will not go to "full idle position" .
Well, obviously the brackets holding the cross-shaft to firewall, #8 and 9, are swapped, but this is the mistake of the drawing, I guess.
I also assume that you did not install the gas pedal lever upside down - that would be crazy as you would have it sticking up inside, in the footwell.
I also assume you tried to see if you can screw the driver's side bracket a bit lower, as it may have the screw holes a bit bigger than the screw diameter and I assume it is not the head of the upper bolt holding this bracket high. So there is no way to tighten this bracket lower.
Then I cannot think of anything else than one of the levers is bent i n a bit wrong way or the lever that is fixed to the shaft turned a bit on it.
I would probably try very unprofessionally to: try to file the holes in the driver's side bracket to tighten it lower or try to shimm it if it helps or bend one of the levers back in place.
I am very curious what is the correct solution here.
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His engine is definitely much closer to the firewall than in my pictures. I would not file or grind anything just yet. It's got to be something we are just not seeing.
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I agree, your engine is WAY to close to the firewall. Are the holes slotted where the trans mount is secured on either side of the of the trans tunnel? Between that, the trans mount and motor mounts themselves and the fixing points of the straps up front between the cross member and the uni-body frame there may be some possibility of fore and aft adjustment of the engine within the engine compartment. Get it as far away from the firewall as possible (taking care not to get the fan too close to the radiator!) It may be a bit tedious to try to do alone - do I hear "garage party?"
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Sunday morning - second cup of coffee. I'm ready to go.
To Mike and mrfatboy - I have been able to gain some separation of the engine from the firewall. I can now remove the regulating shaft without much trouble. It is now removed from the car and I am going to set out on a hypothesis that I have at this time.
If you look at my Photo1 in my previous post you will notice that the first bend in the lever arm as it extends off of the regulating shaft does not seem to have as much articulation as I see in the mrfatboy second photo in Reply #23 which looks to have been taken at much the same perspective as my Photo1.
I know in my previous posts I have been pretty adamant that the lever arm off of the regulating shaft could not have been bent given the material it is made out of and the diameter of the lever arm, but I am willing to concede that it does not look like what I see in mrfatboy's photo.
So I am now going to examine the possibility of altering the geometry of the lever arm. Here are 3 photos of the regulating shaft and the lever arm and an explanation of what I am seeing.
Photo5 - this shows the regulating shaft removed from the car and laid out on a piece of white cardboard and the arrow is pointing to the bend in the lever arm that I am focusing on.
Photo6 - in this shot I have laid the lever arm on the cardboard and have traced the outline of the lever arm onto the cardboard
Photo7 - here I have extended centerline projections of the two parts of the lever arm that make up the bend I am looking at and I have measured the angle of the bend and got 13 degrees as a result.
I know this is asking a bit much - but -do any of you have any idea of what this angle is on the lever arm on your car. I have searched around and can not find anything that even resembles a specification for that bend in the lever arm.
I am fairly well convinced that I can achieve the geometry needed for the throttle linkage to work correctly by modifying that angle. It will take a little heat and some carefully applied pressure but I think it can be done. If I do not get any response as to what the angle might/should be then I will proceed incrementally and do a bunch test fitting and kind of sneak up on the angle that will work for me.
Sun is out and shining here in Libby today so I will be out for a bike ride and let the shop stay quiet for a while.
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Sorry, I don't know what the angle is but to me your lever looks correct.
Attached are photos of the part in two different cars. To me they look like yours, but you be the judge.
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JZ,
See attached picture. Took your picture and see the obvious issue with your linkage rod.
Do this fix and it should be ok again.
Walter
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I think Walter has it. The piece between the two "elbows" is straight on other pictures. Yours is bent. Straightening it in this place right below the upper elbow would move the linkage rod way aft.
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Well it seems as if an answer has finally surfaced. As pointed out in the previous 2 posts from Walt and Pawel66 the bent center section of the lever arm looked to be a likely source of my faulty linkage geometry.
I placed the bent section on my bench vice anvil surface and using a 3 lb. sledge was able to straighten it out and gained about 20 mm of travel. That, along with the little bit of gain I got by being able to get the engine to move forward (another 20 mm) is enough for me to have the linkage work without hanging up on anything.
Thanks to all who choose to wrangle with this dilemma of mine, reading through the posts, and offering up photos to use for comparison. Hope I can be of some assistance to others in the future as my breadth of experience expands. Still have a ways to go before I get this thing all back together but at least I can now move on with my restoration.
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Main question for me would be what bent your throttle linkage? I would imagine that it happened during installation or removal of your engine which is why I always remove all of the throttle linkage before I start that job.
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As soon as I saw your photo #5, I said to myself, "that arm was stepped on or something was dropped on it while it was laying on the floor or on a bench!"
The best thing is that the fix was realtively simple, and you can move forward with your project. Bravo!
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As to what may have been the reason the lever arm was bent as it was - well - I am not going to dwell on it too much. All I can say is that I am happy to be able to move on with my restoration and that in future disassembly efforts I will be more careful and take a hell of a lot more photos.
Thanks again to all. jz