Driveshaft balancing

[n/a]

Hello everyone,
Althought I've been a member of this Pagoda group since the sites fomation this will be my first posting. Seems that most of my questions were answered in past postings and I found that I rarely had anything to add that hadn't been better said before. Before getting to my question I should introduce myself.
 
My name is  Robin from Calgary, Alberta. I've owned my car, 1971 280SL for a little over a year and a half. For the curious I've posted an owner's scrapbox at http://members.shaw.ca/pagoda113/index.htm  It pretty much tells my story.

My question concerns drive shaft balancing. My U joints are a little sloppy and I've purchased a new factory assembly (U joints and shaft). Is dynamic balancing required or can I just drop the old shaft and pop in the new one.

Thanks in advance for your help, Rob
GO FLAMES!!!!!!! Canada's last hope

[Richard Madison]

Rob:

Don't know about U joints. (Didn't even know I had any) but your web site is great...some nice beauty shots, good advice, and encouragement for Pagoda owners...even a link back to this site.
Richard M

[Naj ✝︎]

Hi, Rob,
Really enjoyed your site and comments. Great job.
My guess is the new shaft will be balanced at factory.
naj

65 230SL
68 280SL

[Cees Klumper]

Excellent site, very recognizable en a lot of fun to browse through! You have The Pagoda Virus for sure.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Tom]

Rob,

Nice Website-nice job on the car.  Your details of how to color sand is excellent.  Most do not even know that they have orange peel and that getting that "deep wet look" requires the extra steps that you detail in your site.

Why not go with the extra step and check the shaft to ensure it is in balance?  Easy step while it is all out.  Would not count on this being done at the factory unless you can see some weights attached to the side of the shaft.

Best,

Tom

_____________________________________________

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
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[Cees Klumper]

The driveshaft and U-joints on my car were put in new by the PO and the shaft does have some weights stuck to it for balancing. I don't know if that was done by the factory or not, but they do have the exact same color as the shaft itself, and it looks like the whole thing including the weights was painted after it was balanced, so that would seem to indicate a factory-job. I would check to see if your new shaft has weights added to it or not.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[n/a]

Hi guys,

Thanks for your quick responses and the kind comments on my scrapbook.

Cees, that was a great heads up on the little weights. I pulled the shaft out of the box and sure enough there's a little balance wafer attached to the shaft. I'm still a little muddled by an old posting I remember reading about marking the position of the front and back sections of the drive shaft to maintain there relative position on reassembly. Am I right to assume that this is a balance issue between the 2 parts? If so, do I just pop in the new rear shaft and ignore any relationship to the front shaft? The BBB describes the replacement process but mentions nothing about the balance between the 2 parts. Am I missing something here or am I just worrying about a problem that doesn't exist? Wouldn't be the first time I paralysed myself with what ifs.

Tom, Colour/color sanding could merit it's own thread. It produced the single most dramatic improvement to my car's aesthetic. The best part is that it's the least expensive upgrade I done in terms of material cost. Water, dish soap, sandpaper and cutting/polishing compound. Time invested was the killer, I lost count after 60 hours. It's a great winter project when the car is laid up for months and you can tackle a panel at a time. It's also a fairly easy skill to master The paint job is always the first thing people compliment me on. Little do they know that it's really an average respray done by the first owner at least 18 years ago. The magic is in the colour sanding. I'd be happy to answer questions for anyone willing to tackle the project.

Best regards,
Rob

[Cees Klumper]

Just guessing here, but it could be that certain of the driveshaft parts front-to-back, once installed, start wearing with a certain pattern and that this is why was advised, when temporarily disassembling, to mark the relative orientation. If the BBB does not call for any particular procedure to align the front and back sections, then I'd say it's safe to assume you don't have to.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[mdsalemi]

I can assure you that driveshaft balancing is quite important.  In fact, EVERYTHING that rotates at speed must be balanced on this and any other car.  A driveshaft that does not go through a balancing process may be somewhat balanced (just as some tire and wheel combinations don't require weights)but more often then not will impart some vibrations, perhaps only at a certain RPM.  This could be one of those very elusive problems to solve!

I have had good experiences with Driveline Service of Portland (Oregon).  Drivelines are their business, and anyone interested in their drivelines or this thread should go here to read; it is quite fascinating:

http://www.driveshafts.com/merc_u-joint-overview.html

Michael Salemi

Mike Salemi

[Benz Dr.]

Drive shaft balance is critical. ALWAYS mark everying before you pull anything apart. The 280 driveshaft can't be rebuilt at home.

  It's possible to use a gear clamp on the drive shaft and keep turning it until any small vibrations are gone.Actual amount used for balancing is very small.

Dan Caron
 SL Barn

Daniel G Caron

[n/a]

Hi Dan,

I'm assuming you mean don't try to press the U joints onto the shaft at home. Wouldn't even think about attempting it. I thought about ordering the 2 U joints and having them installed by a drive line specialist who's familiar w/ Merc. After talking to him I decided against it. He told me if I wanted perfection that I should order a new shaft from the factory. So I did. It turned out being only 90 bucks more than the cost of the 2 U joints and labour to press them on and balance the old shaft. For that small of a spread I didn't want to jerk around with the old shaft.


From what Cees pointed out about the weight on the shaft I now know it's factory balanced. My question is, do I just pull the old one out and put the new one in? Or is there some kind of balance issue with the front shaft coming off the transmission.

By the way Dan, I don't even know if you remember helping me with pre- purchase advise a couple of years. I was a jerk for never thanking you so I'm do it now. Anytime you're in Cowtown you've got a bed and beer at my house.

Rob  

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[erickmarciano]

by the way what was the price for the shaft?

1971 280sl
1962 VW
1954 Allstate vespa
1958 gs150 vespa
1962 gs160 vespa

[Cees Klumper]

These shafts list for 400 euros (less than $500) here in Holland. Not bad I think, compared to the cost of some other parts, like the warmup thermostat of the 230 SL's injection pump.

Dan's idea, to put a gear clamp (I am assuming this is something similar to a hose clamp?) around the shaft and to keep turning it until the vibrations are gone, sounds very good. Once I replace my one bent steel rim (which is causing me just a slight vibration around 60 MPH) and there's still some vibration left, I will try this.

Just FYI - years ago I had to remove some horrendous vibration coming from the driveshaft of a Triumph Spitfire I had bought. I did this by putting the car up on blocks and, with the engine running and the car in gear, I carefully held a chalk to the driveshaft to see exactly where it was not centered. By shimming the u-joint, I was able to remove all the play in the first try.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Benz Dr.]

I guess I don't remember who I help out. It's sort of moot since anyone can benifit. But thanks just the same.
Sounds like a new shaft is the way to go on a 280. The 230 is very fixable at home but may benifit from balancing.

Dan