Should I or shouldn't I, to bush or not Options

[iankarr]

Hi Guys,

I've disassembled the rear of the bumblebee and the control arm pivots and bushings look to be in good shape.

My plan was to blast and powdercoat the control arms, which would require removing the pivots/bushings (due to the heat)...but I hear re-installing these can be a beeotch. And I generally prefer keeping as much OEM as possible.

So...do you think it's worth leaving the bushings and pivots alone and just painitng the arms? I'm aiming for this bumblebee to be a solid #2 car when done.

Thoughts? Thanks!

[bbrock]

@Superhawk996 I like asking dumb question so here is another. Do you think there would be any benefit in coating replacement rubber bushings with cold vulcanizing cement before pressing them in? I know you can't really answer without having data to know what specs we are shooting for but curious if that would help bond the bushings to the tube which seems to be what vulcanizing does. (IMG:style_emoticons/default/popcorn[1].gif)

[Superhawk996]

@Superhawk996 I like asking dumb question so here is another. Do you think there would be any benefit in coating replacement rubber bushings with cold vulcanizing cement before pressing them in? I know you can't really answer without having data to know what specs we are shooting for but curious if that would help bond the bushings to the tube which seems to be what vulcanizing does. (IMG:style_emoticons/default/popcorn[1].gif)

I don't think I would.

I should be careful with the term vulcanizing before I get eveyone wound up. Vulcanizing isn't really a bonding process.

Vulcanizing is the process of modifying the rubber itself for durability and elasticity.

I belive that the OEM bushings are probably bonded (probably with chemicals & heat - thus the term vulcanized bond) to the trailing arm and the pivot shaft. The other option is that they are press fit so tightly that for all practical purposes, they are mechanically gripping the shaft and trailing arm to the point that they cannot move relative to one another.

So why not bond them with the cold vulcanizing cement?

My reasons would be:
1) Not sure the cement is compatible with the aftermarket rubber and/or could cause degradation to the rubber.

2) If or when the cement bonding gives up and breaks free, it might actually then work against you by allowing easier movement of the parts realtive to one another. Relative movement will lead to rapid wear and won't have bushing rates anywhere near OEM intent rates.

3) From everything I've read (remember my trailing arm bushings are shot), the amount of press work and swearing associated with installation is pretty intense. Having to deal with the possibility of having the cold vulcanizing cement partially curing before I get everything seated home and then inhibiting installation seems like a risk I wouldn't want to take.

Having said all that, I haven't done this job yet myself but the pitfalls are almost enough to make me consider poly-bronze bushings and I know I'd hate those for a street car based on prior experience with them.

I don't wan't to promote myself as some sort of expert on 914 trailing arm bushings. I'm just sharing my rationale on why I'm not inclined to change out a set of trailing arm bushings that aren't otherwise damaged based on my professional experience with the nuances of bushings. There is more to them than meets the eye.

Ask yourself this question, how many vintage cars, trucks, vans, etc. are out there on the road that haven't had all the bushings, trans mounts, and/or engine mounts replaced wholesale? Quite a few, and they still get around just fine. Could they be better? Yup, I'm sure of it in some cases. Could they be worse, yup, lots of cars out there with all sorts of aftermarket bushings & mounts that actually made them worse.

No way to know with certainty without objective data.

Based purely on reported outcomes with the various aftermarket rubber bushings from our usual vendors I think they will be just fine for our hobby cars and I don't want to come off as snubbing them. I'm glad the parts are availble. It's really just the question of effort vs. reward. Each of us will have a different sweet spot.