rear-end shudder/shake at low RPM

[aaronlee133]

Hey fellas,

Question: Has anyone experienced rear-end shudder at low RPMs after installing prothane 4-links bushings in the rear? Not sure if its a common symptom but I didn't have this issue with the old rubber bushings before the swap.

Thanks,
-Aaron

[jondee86]

Hard urethane suspension bushes are well known for increasing the noise
and vibration levels inside a car. I can't guarantee that your shake/shudder
is now much more noticeable due to the bushes. But the chances are that
if you didn't change anything else, then the bushes are to blame.

If you had a little bit of clutch shudder before, the rubber bushes could have
been absorbing it to the extent that you didn't feel any shuddering in the car.
Does it only shudder when you are slipping the clutch ? If it shudders when
the clutch is fully engaged and the car is moving slowly, then it may be some
kind of ignition or fuel problem that cause rough running (uneven power
strokes) at low rpm.

If there are no issues once you get a few revs/bit of speed on, then just
get used to the shuddering. Welcome to the world of urethane bushings

Cheers... jondee86

[aaronlee133]

Thanks Jondee. Vibration is noticed when fully engaged. Ironically, I put the rear-end on jacks and then started the car. Everything engaged fine until I went to go cut the engine while car was in 1st gear and thats when I noticed the shudder. Felt like it was coming from the u-joint which connects the prop shaft to the pumpkin. When I had the drive shaft off I noticed that that joint didn't feel as smooth as the other front 2 joints. Hence, I'm thinking its a driveshaft issue. To your point however, I think the worn rubber bushings I had on previously helped to mask some of it and now the urethane bushings make it much more noticeable. Good thing is, its only at low rpm and only then sometimes. I know how to modulate the throttle when accelerating and shifting to avoid the problem tho.

[mad_86]

CHECK your Drive shaft Bolts make sure they are Tight

[assassin10000]

If the joint is notchy or clunks/loose, replace th r driveshaft unless a shop nearby can replace it.

Andrew

[SgtRauksauff]

I would also recommend making sure your tires are balanced. they do change balance over time as they wear, and moving to harder bushings can cause all sorts of noises and bounces to come through.

the driveshafts on these normally have the u-joint staked into the yoke, so not normally serviceable. However, with careful grinding of the stakes out, they do make u-joints with the circlip that goes on the inside of the yoke, around the ujoint leg, rather than outside of the cap in a yoke groove.

If I remember correctly, the u-joints are a common size and easily sourced once the yoke machining is done. I have never had to do it myself, but plan on it eventually when these joints just wear out....

[davew7]

Search for radco, Radcoent/Uniiversal, for a replacement stake-in type U-joint for the AE86 drive shaft. This info is about 10 years old, So hopefully they still carry them. I was able to grind out the staking, replace the joint and just restake [after carefully centering the joint in the yoke]. DaveW7

[SgtRauksauff]

Another source is Rockford Driveline

http://rockforddriveline.com/replacem.htm

no affiliation, but they're only a couple hours from me, so basically "local".

--sarge