Some questions about inner trailing arm bushings...

dd74 · 10-26-2005, 01:30 PM

1) Have these ever failed on you, as in cracked, worn out, etc?

2) What is their lifespan? 10 yrs? 20 yrs? 30 yrs?

3) Is it a worthwhile "while you're in there project?"

4) How much wood could a woodchuck chuck if a woodchuck could chuck wood? (optional)

Thanks y'all.

KobaltBlau · 10-26-2005, 01:37 PM

I think Grady Clay told me (offline, in "real life") that they seldom wear out. In any case, I did hear that from a reputable source.

You might look at as an opportunity to put in elephant racing sealed monoballs

Don't use polyurethane here as it needs to move on more than one axis.

dd74 · 10-26-2005, 01:46 PM

Andy - I've heard the same. If anyplace on the suspension, this is the place to undoubtedly put monoballs. The drawing was...er...handy from somewhere else...

DW SD · 10-26-2005, 01:47 PM

1. no
2. don't know.
3.Seems like it is a good while you are in there thing. You'd hate to have to pay someone to realign the rear of your car and rear corner balance, etc, because you didn't spend $200 to replace those with the monoballs (while you are in there). As the rubber wear out, cracks, etc, I think you will get excessive movement "play", which would change your alignment settings under load.

I drank the cool aid and replaced them with Chuck's.

4. see Chuck

Evans, Marv · 10-26-2005, 02:24 PM

I just replaced the bushings in my aluminum swing arms with monoballs. The swing arms were from '76, and the rubber wasn't worn out by a long shot. The exposed rubber around the rim of the steel insert was cracked, but the unexposed part was fine. I took them out because I thought they should be replaced (while I was in there) since they were close to 30 years old. They would have been fine, but I'm glad I replaced them with monoballs. I figure it's a decent cost spread over another 30 years (maybe).

randywebb · 03:12 PM

My understanding was that they got hard - not that they fell apart.

re #4 - My MS concerned rockchucks, a related species (that is more social). I discovered that the answer to #4 involves the gradient of the Chuckability function, integrated over the Rockworthiness Index. I put that in my final seminar, so I expect that you can simply substitute a Woodworthiness Index instead. *

* This valuable information is your to use for free - a consultant would charge you $300/hour for it...

Elombard · 10-26-2005, 03:21 PM

I think it is the most important bushing to replace period. I am sure given modern technology and if the budget suported it Porsche would never have used rubber. By design the rubber has to bind when it moves in 2 directions. Seconds of your lap time??? probably not :-)) I am doing mine in a few weeks. Cant wait.

dd74 · 10-26-2005, 03:29 PM

Quote:

Originally posted by randywebb
My understanding was that they got hard - not that they fell apart.

re #4 - My MS concerned rockchucks, a related species (that is more social). I discovered that the answer to #4 involves the gradient of the Chuckability function, integrated over the Rockworthiness Index. I put that in my final seminar, so I expect that you can simply substitute a Woodworthiness Index instead. *

* This valuable information is your to use for free - a consultant would charge you $300/hour for it...

LOL! Yes, but can a woodchuck chuck a monoball?

Superman · 10-26-2005, 03:45 PM

He'd chuck all the wood that a woodchuck could if a woodchuck could chuck wood.

drums · 10-26-2005, 04:08 PM

I did so many things at one time [front and rear] that I can't tell what the mono balls did for mine. The car just handles so differently [excellent] after all of the work.
Do mono balls make a stock/semi stock car handle markedly different?
If so, how did it effect the ride?
Drums

randywebb · 10-26-2005, 04:09 PM

"can a woodchuck chuck a monoball?"

- I think we'd better just leave their sexual deviances to them... if you ever seen otters get it on, or a "copulatory ball" of hundreds of rattlesnakes... well, not every man can assimilate that info and stay sane...

rexav8r · 10-26-2005, 06:35 PM

I just replaced them on my car this spring. I went with the OEM metal/rubber pieces.

Would have rather put in the monoballs, but I had a big chunck of credit that I was able to apply to the somewhat expensive OEM pieces to make 'em pretty cheap.

Anyway, I believe the ones I replaced were the originals (1969 build date on the car). The rubber was pretty dry and cracking, but I didn't notice any extreme deformation. The old ones were a BEAR to get out (especially the FIRST one on each arm). I used a 6 ton shop press (Thanks Evan, Fuelie600) and had to get creative with some metal & wood blocks.

On my future fantasy/project it WILL be Elephant all the way around !! Front & rear !!

SCOTITUDE · 12:16 AM

I had the same questions before I did mine. The old bushings didnt deteriorate but hardened up to where they had no deflection keeping the swingarms from moving. Here is what was explained to me. The stock rubber bushings have one setting. Any movement of the swingarm of the one axis and the rubber bushing fights to keep it static. This limits its range of motion. I was looking for more camber (3deg) in he rear and the monoballs would let the swingarm adjust to the higher camber settings where the rubber bushings would fight the movement. It was an easy install with the swingarms removed from the car. Minor force from a floor press needed to press the old ones out and the new ones in. I have been very happy with the setup and they are $ well spent.

Shuie · 10-27-2005, 03:57 AM

I just replaced mine last weekend with a set of the hard poly bushings that Pelican sells. The old ones were pretty deformed.

rexav8r · 10-27-2005, 04:30 AM

SCOTITUDE, (& Shuie),

I think the HARD POLY bushings are the ones that only have "one setting" as you put it, or rather one axis of rotation.

The arm DEFINITELY moves & NEEDS to move along MORE than one axis !!

The OEM are rubber so they "deform" or rather ALLOW movement in MUCH more than one direction, albeit not as good as the movement allowed by the monoballs.

The HARD POLY bushings act more like a "shaft bushing" only allowing the arm to rotate or pivot along the axis of the bolt going through.

I actually bought the same thing this spring. However, I ran into another thread like this one that convinced me to just go get either the monoballs or the OEM. I think it was Grady in that one too !!

randywebb · 10-27-2005, 12:03 PM

I'll just add that the hardening and 'cold flow' of these things happens as a function of time - not really mileage so much.

So: even if your 20 old car has low miles, it still will likely need to have these replaced.

dd74 · 10-27-2005, 01:14 PM

Guys - thanks for the help. Very convincing testimonials.

safe · safe's Garage

But how much do they impact the ride?? If you just replace these bushings, can you tell the difference?