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Posted by: Ecke Liebhaber Mar 15 2018, 08:58 AM

I'm replacing the rear bushings and want to allow lubrication via grease fitting.

Do the inner diameter of the bushings pivot on the shaft or do the trailing arms pivot on the outer diameter of the bushings?

Bushings seem tighter on the shaft, and that surface area is much smaller than the o.d.

Posted by: malcolm2 Mar 15 2018, 09:15 AM

I have seen bushings with zerk fittings, so the grease must go between the outer diameter and the arm. Maybe that is only the front bushing I saw a fitting on.

But isn't the bushing there to hold everything in place as it twists or rotates. Would grease cause or allow over rotation?

I guess I need to find a picture, it has been too long since I re-bushed.

Posted by: Ecke Liebhaber Mar 15 2018, 09:15 AM

After 20 searches I found the answer;
Bushings are fixed to the trailing arms, vulcanized in place originally.

Install the bushings, ream i.d. of bushing with a sanding drum, use JB Weld to 'fix' bushes into trailing arm, install pivot shaft while epoxy is curing, then drill for grease fittings.

Thanks to posts by Eric Shea and Dave Darling

Posted by: malcolm2 Mar 15 2018, 09:18 AM

Won't that be for the "plastic" bushings? I used Elephant Racing rubber and no JB Weld. JB Weld seemed to be a hack fix for slippery delrin bushings.

Posted by: Mikey914 Mar 15 2018, 09:30 AM

The factory process I doubt was vulcanized. It would give you a part that was pretty much serviceable. That being said, the original process was very much like the A arm bushing install. Heat was definitely involved, just not fully vulcanized,

Posted by: HalfMoon Mar 15 2018, 09:31 AM

Wouldn't the zerk itself hold the busing in placer and keep it from rotating?

Posted by: Ecke Liebhaber Mar 15 2018, 12:50 PM

Bushing is supposed to rotate on the shaft.
Bushing is supposed to be fixed/attached to the trailing arm.
Bushing is not supposed to rotate in the trailing arm.

Hack?
Well, if the bushings are aligned by the pivot shaft and the epoxy allowed the bushing to be perfectly self align and then that same epoxy keeps them perfectly aligned and 'fixed to the trailing arm i.d., I do not see that as a 'hack'.

I see the method as the correct way to install bushings that keeps the bushing from rotating in the trailing arm and also keeps the bushings aligned and will do so in the future, which will result in the bushings lasting longer.

I use the same method for the front suspension, and sway bar pivots if the bushing has any tendency or probability to be able to rotate in the bushing holder (what ever that may be).

Suspension moves freely without and binding, and that is the ultimate goal.

Posted by: Eric_Shea Mar 15 2018, 12:58 PM

Elephant requires all races be JB Welded in place. It's an awesome way to keep a solid bushing in place. Reversible as well.

Posted by: malcolm2 Mar 15 2018, 01:53 PM

I started with Rebel racing stuff. Sumpin' just was not right with them. And JB Weld was recommended. Not supplied tho. Not gonna hack my suspension parts. There was a 1/4" gap to fill with JB weld. That is a HACK. Maybe they sent the wrong stuff, but I returned them and moved on.

i got no races. I installed all rubber front and rear elephant bushings. They supplied the tools, all I added was some dish washing liquid, the end.

I don't plan to doing any racin'. https://www.elephantracing.com/porsche/911/bushings-bearings-for-911/rubber-bushings/#prettyPhoto-gallery-365/0/

Posted by: Eric_Shea Mar 15 2018, 01:58 PM

Yup. You did the right thing. Rubber is the way to go for your setup. And NO... JB isn't used to fill 1/4" gaps. Something definitely wrong there. That doesn't sound like Rebel stuff. They're usually pretty spot on. ER PolyBronze is a precision fit so, they need to have a race JB Welded to the arm to maintain a consistent surface. It's totally acceptable and, get JB over 450-500 degrees and it comes right off so, no irreversible effects to the arms.

Posted by: Ecke Liebhaber Mar 16 2018, 05:41 AM

I agree with Eric. 1/4" of 'slop' is odd, and filling that with epoxy is definitely a 'hack'.

That is massive, and using the epoxy to fill a void is not a good practice.


JB Weld is machinable, and has great strength in the right application, such as the large surface area of the trailing arm bushing inside of the trailing arm.

My bushings will rotate in the trailing arm i.d., but have only a tiny bit of 'wiggle'.
The trailing arm pivot shaft aligns the bushings and even without the epoxy, the bushing no longer rotate easily, but they do need to be 'fixed' in the trailing arm i.d.
I will be drilling the bushings to allow grease to get to the i.d.. and the outer part of the 'grease hole' will have a larger i'd. to will allow the zerk fitting to fit. This will also locate the bushing, but the film of epoxy around the bushing is massively strong.

Posted by: Eric_Shea Mar 16 2018, 09:27 AM

Posted by: Andyrew Mar 16 2018, 09:43 AM

Very important picture here, This shows the rubber BELOW the steel. If its taller than the steel your trailing arm will constantly come loose. Many times this needs to be sanded down (As it looks like this piece was)