Author Topic: Differential trailing arms  (Read 240 times)

230slhouston

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Differential trailing arms
« on: August 02, 2020, 01:21:56 »
Hello,
I am making good progress on assembling my differential. Question, on the trailing arms? at what angle do  I bolt and tighten them on the tubes. Do install the, loose and lock them once I install the diff back and adjust it?
Also which side does the donut rubber go? The original ones are pretty worn out, I cannot tell from it.

Thanks,
Maistran
Maistran (MB)
66 230sl white

Harry

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Re: Differential trailing arms
« Reply #1 on: August 02, 2020, 11:55:57 »
It’s been a while since I replaced mine, and I recall at the time there were two schools of thought on orientation.  I also recall that the the through-hole was tapered, as was the formed mating feature on the car.  And when matched, this resulted in the rubber also matching the geometry of the trailing arm.  So despite the comments otherwise, I installed the rubber isolators in this manner.  No issues and that was several years/miles ago.
Harry Bailey
Knoxville, TN
1966 230SL
Automatic

wwheeler

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Re: Differential trailing arms
« Reply #2 on: August 02, 2020, 15:50:33 »
In my opinion, you should secure the bolts in the neutral position simulating when the car is at rest on level ground. That way, there is equal stress on the rubber bushing as the axle travels up or down from this neutral position. If you torque the bolts with the axle hanging down, it could over stress the bushings when the axle travels up from the neutral position. I am not sure how critical this is, it just makes sense because the rubber bushing is flexing internally. If it were a pivoting type joint, it would not matter.     

As far as the bushing position, the way you have it in the picture is the way it goes up into the arm. EPC has a good picture of that in the rear axle section. The Niemoeller site should also have a good one as well.
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

230slhouston

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Re: Differential trailing arms
« Reply #3 on: August 02, 2020, 16:07:58 »
Wallace and Harry thanks for the information.
Hard work but feel good to see this coming together.
Maistran (MB)
66 230sl white

wwheeler

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Re: Differential trailing arms
« Reply #4 on: August 02, 2020, 17:48:24 »
Looks good! When you go to tighten the bolts, you might take a socket and grind the face so that there isn't a chamfer on the leading edge. The bolts have such thin flats and the torque is so high, you need all of the surface contact between the socket and the bolt you can get.   
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

Benz Dr.

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Re: Differential trailing arms
« Reply #5 on: August 03, 2020, 05:13:30 »
The measurement from the front of the pinion flange to the front edge of the pin is critical and should be 158 mm. We use a carpenters square and a tape measure to adjust it.

 The pin going through your trunk floor must be at a 90-degree angle to the left axle.  I use some cardboard under the middle of the diff until I have the left axle tube level. Then I use a different level to find the 90 degrees needed for the pin. Make sure your floor is level before you begin. 
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

230slhouston

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Re: Differential trailing arms
« Reply #6 on: August 03, 2020, 14:24:07 »
Thank yo for the replies.
Should I install the compensating spring prior to installing the diff?
Maistran (MB)
66 230sl white