Just located the clunk in the rear suspension, trailing arm bushing is bad.

so what are my options for replacement?

It is autocrossed and set up reasonably well so someting in the perormance vein is what I am looking for.

poly Graphite

Delrin _ is there an option to do this without Tangerine's kit

Poly Bronze

Sources?
what are you guys running?

Thanks

Your choice they all work. I will also say its all about proper fitting and making everything square and true.

I run Poly Bronze from Elephant racing, arm will drop from weight, smooth as glass on rotation. I highly recommend but they do take proper fitting.

You forgot two choices, full on rubber, and roller bearings. the first has softness issues, but compliance can be a good thing if you drive it on the street for long distances.

Love my Elephant Racing polybronze front and rear.

Rebel a Racing also makes a nice alternative that uses a polymer Teflon bushing that never requires lubrication so no grease fittings needed!

I've been curious about Rebel vs. Elephant as I am hopeful to actually start building my car at some point next year. Does anyone have personal, real world experience with BOTH to comment about ?

Here's a few links:

http://www.914world.com/bbs2/index.php?showtopic=79299

There are 2 things I do differently with each install we do:

1. I like to use the McMaster 3x1" sanding drum now. "Much" more even ream on the inside of the bushing.

2. I JB Weld the bushings in place once I have confirmed the fit. Let them sit 24 hours before drilling and tapping for the 6x1 bleeder.

http://www.pmbperformance.com/catalog/item...565/5297602.htm

Awesome how to post

thanks

Roller bearings ride really really nice

I have the Tangerine bushings and had Chris put them in. Excellent product and he does a couple of things that make them fit better than other ones.

I used Elephant Bushings but I have a set of poly graphite that Eric_Shea sent me sitting in a drawer in my tool box. I'm not sure what they're worth but if you want them we can figure that out. Eric sent them to me as part of a set of trailing arms he converted to 5 lug for me... Figure 2/3rds of whatever Eric sells them for...

I did my installation like the above as Eric suggested.

Had a 4 wheel alignment done....so far so good...no squeeks. I put two zerks on each arm through each bushing.

I think I did a thread on it as well.

....oh....I used the harder 70D ploy bushings.

Are the rebel racing rears actually something you can purchase? When I bought the fronts it looked like the rears were still in development, and there is still no button to by them on the website.

That being said, I LOVE their setup for the front, they are the slickest things I have ever felt when installed and they look like works of art. I have never personally had the elephant bushings, but I have seen them first hand, and I would say the Rebel racing ones appear to be a finer manufactured piece, AND they don't require any lube EVER, which is the main reason I went for them. Ride quality with them is amazing after using poly ones that basically destroyed the front of my car.

Now, I currently have some pretty strong feelings about rear bushings. I have studied the rear design quite a bit trying to figure out what would be ideal, and of the solutions I have seen (rebel not included because I am not sure they exist) I don't think there is an ideal choice. My thoughts on each are as follows.

Rubber: At this point I think they are the best option but mainly because they are what the rear suspension was designed to use (more on that later). Downsides: Expensive for what they are, they are soft, removing them was a nightmare so I can only imagine how hard they would be to install. The main reason I think they are the only way to go though has to do with the thrust surfaces, specifically on the inner pickup points. Think about what happens when you are setting the rear alignment, the inner control arm mount is fixed and when you move the outer pickup point the angle and space between the control arm and the inner mount change. Rubber bushings will compress at this point allowing for the adjustment, none of the solid bushings will which means you either don't set your rear alignment, or you create a huge pressure/friction point where the rubber bushing would normally compress.

Poly: Easy to install compared to rubber especially when you can drive over to Erics and have him fit them to the shaft. Next to impossible to install properly due to the fitting of the thrust surfaces and their changing dimensions when aligning the rear. I currently have these on my autox car as I needed a quick fix but they will be coming off soon. Things I don't like about them: Getting them perfect is a pretty much impossible and a TON of trial and error. Even installing zerks you are still only lubing the shaft surface and any lube you apply to the thrust surface when installing is gone in a couple weeks and you are squeeking all over the place. That is probably my #1 problem with poly bushings, all the friction. Rubber bushing are pretty much stuck and all movement is accomplished by twisting of the rubber, the poly bushings have to slide on a shaft that was not designed for this purpose and (even worse) are grinding on your suspension pickup points, a place already prone to damage. So, best case, the thrust surface wears on the poly side and once you get even the slightest bit of wear you get a nasty clunk in your rear end, worst case you damage your inner suspension ear from grinding on it all the time, something that may have happened anyways when you have to bend it to get solid bushings to align properly. I have been playing with the idea of thinning the thrust surface of the poly bushings and adding a rubber backed race to allow for proper alignment as well as a better surface for them to ride against. This would also take a lot of the trouble out of fitting them properly as compressible rubber would fill any potential gap between the thrust surfaces. I am not sure if there is enough space there for something like that to work though.

Elephant polybronze: From the set I was inspecting over at Erics shop, they are defiantly an improvement over straight poly. They appear to have an added race for the thrust surfaces and the all the friction services were actually designed to be friction surfaces and have been machined to each other properly. The issues I see with them are: 1. they require regular lube. 2. From what I can tell they don't address the compression issue on the inner suspension ear. I have not personally used them so I can not comment much more, but they seem like they may be a good solution for a track car that sees regular maintenance.

Rebel Racing: Can anyone confirm their rears have been produced? If so, given the quality of their front setup, these will most likely be the next ones I will try.

Bearings: I don't really have an opinion on these as they seem expensive given the other options available so I never really considered them. The Elephant site claims there are wear issues, and as with all the other solid bushings they don't address the compression point on the inner suspension ear.

I'm not sure if the Rebel Racing rear bushing kit is in production or not. I assumed that it was but have not looked at their website in a while. I do have a set of their front control arm bushings and they are impressive. The quality of these is second to none. I can't really think of any other aftermarket components that look as nicely made as the front bushing kit from RR.

James - I think you have to make a differentiation between poly and delrin. IMHO, Eric is not clear on what his bushings are to the average person "harder Delrin style polyurethane bushings". They are either polyurethane or Delrin.

I'm not going to spill all of Chris' secrets, but he makes sure the bushing are pressed to the arm and then the shafts are free inside them. He also has a way to control end play which makes sure the shaft stays still and the arm turns around it. It's the best setup I've seen.

Something else that most people don't account for is that the shafts wear near the threads on the inner ear. That needs to be inspected and the shafts replaced if worn. I don't know anyone who has those except for Chris.

There was a nice article in Grassroots Motorsports last month or the one before. There is a lot more that goes into a polyurethane bushing than you would think.

Delrin is a type of Poly/Plastic, but it is milled out of a Block. Poly Bushings are Molded.

Delrin is Much, Much Better!

I agree with most of what you have said. However on the poly install you need to "thin out" the face of the bushing to expose the knurling of the pivot shaft so that it remains stationary and pivots around the bushing. It is a compromise for sure as then the bushing turns around the pivot shaft and slightly engages the face of the suspension console when it is racked hard. It was not designed originally for that, and if I were AXing the car I wouldn't have gone that way because of the "racking" that happens. The car was a pain to align afterwards for sure, and I took great pains setting it up.

I agree with ....I think Matt....that Chris takes a lot of effort to set it up right with the parts he uses...and if he wasn't on the East Coast I would have had him do mine.

Delrin is polyoxymethylene as a high molecular weight polymer - I am pretty sure that the Delrin brand is a homoplymer. It can be molded or machined. It is hard and has an unusually low frictional coefficient.

Ball bearings for roller rockers and suspension bushings are questioned by many because they do not actually rotate as intended in use. They rock back and forth. Sometimes this leads to wear points.

I recently talked to a retired bearing engineer. He worked his entire career designing bearings and fitting them to specific applications. He also consulted on the M96 replacement bearings you see offered everywhere. His thoughts on roller bearings in suspensions is that they should be fine. They are used in many other applications with similar loads and rotation speed. He didn't think they would have the problems that are pointed out at ER.

I bought the Delrin ones. It'll be a LONG time before I have them on the car. I won't have a lot to compare them to, but from what I've read here and elsewhere, the extra $20 per set seems like money well spent.

They're actually relatively easy to replace--pretty much a bolt-on operation.

Step 1- Unmount trailing arm from chassis.
Step 2- Throw away old trailing arm.
Step 3- Mount new trailing arm.

... The stock rubber parts are vuclanized to the trailing arms, so the "correct" way to replace the bushings is to replace the arms.

--DD

Dave,



I thought the whole part is vulcanized as an asssembly and these assemblies are NLA.

There is no other solution than to replace the bushings.

Edfucate me.

He just did. You can (but wont) replace the entire assembly. Too expensive.

Stand edufucated.

How much and where?

I wasn't trying to say that getting the parts was easy, just that the labor was easier than you would think. Because you replace a lot more than you would think you need to--you replace the whole trailing arm.

I do think they're NLA, but you might find some NOS around somewhere. They'll likely cost an awful lot of money, so they're not exactly a good option... But that is the stock setup.

--DD

I might have a Set of Elephants For Sale - won't know til after the weekend!

I went gonzo 3 years ago when Shine Racing sold their last stash of 914 roller bearing bushings and have them front and rear on my 914 cafe racer. Sure, they offer no "play" but they are also so efficient that they go a long way to smooth out most bumps on the street. I've never regretted the decision. This winter I hope to take them apart and inspect them

Excellent info guys. Will be getting to bushings shortly on my project so I appreciate the insights.

I have Elephant Racing bushings on the rear and they're great! I had Tangerine Racing set-up but it was installed incorrectly - no lube was put on the rods so the bushings just "fried" from the friction. It was not the product failure but an install error by a trusted mechanic. I was on a cross country journey and found my way to Elephant Racing's shop in San Jose. They did a great job and it is a quality product. If you don't mind adding grease occasionally I say go with them. I have Rebel's polybronze on the front. They're great too.

I was thinking about the RebelRacing units but have not found any real world experience with them other than this video which did not sound very encouraging. If you read his comments they wanted him to JBWeld them:
https://www.youtube.com/watch?v=wGWdoG1fhjk&noredirect=1

Anyone else installed these?

They make some nice products but have the worst customer service I've ever come across. I've been trying to get a return phone call or email reply for over a year. I have an issue with their rear trailing arm bushing kit. I don't generally like to say anything bad about a vendor but I have literally called them 40-50 times and sent about 20 emails and still have not gotten a response. And, if you do reach them, feel free to tell them I said so!