A-Arm Bumper Stop Issue

[1986swb]

I'm having issues reinstalling new bumper stops in my upper and lower A-arms for my 1986 GMC 1/2 ton, 2wd. I used grease, penetrating oils and even tried using a massive "C" clamp to press in the stops but to no avail.

This is the only thing holding me up from reinstalling my new front suspension.

Any ideas on how to resolve my issue? Much appreciated.

[tvblazer78]

I have always used a flat head with black tap on it so you don't mess the paint up. make sure it's not cold when your doing it or take it into your house and get it up to 80 or so then it should go in a lot better..

[1986swb]

Originally Posted by tvblazer78

I have always used a flat head with black tap on it so you don't mess the paint up. make sure it's not cold when your doing it or take it into your house and get it up to 80 or so then it should go in a lot better..

Thanks for the insight. You got me thinking last night and this morning about using "heat." So thanks to you, I was able, with the help of my friend, to successfully install the bumpers into the A-arms. But not without issues. Here's how:

1. Lower A-Arms: Heated up my lower rubber bumper stops with a HEAT GUN until it was pretty soft, but not butter soft. I applied direct pressure on the bumper sitting directly over the A-arm slot while my friend used a blunt (not sharp) flat blade screwdriver/pry bar and BFH (Big F'ing Hammer) to slowly but surely tap the arrow-shaped end into the slot, working side to side. Take your time as you don't want to a) chip your paint and b) tear your bumper stop.

2. Upper A-Arms: Did the same as the upper a-arms but since GM discontinued the upper bumper stops, I had no choice but to use polyurethane stops, as I was under time constraints (I could not wait a week for the new stops). They are much more slippery and not as durable as rubber. They went into the slots with some effort but they also suffered some damage -- tore off part of the arrow-shaped ends. They will still work though.

Lesson Learned:

1. If you plan to reuse your A-arms, leave those bumper stops in place and restore/paint around them. These bumpers should last you for the life of the vehicle.

2. If you decide to remove them, go with natural rubber. If GM does not carry them (Classic Parts of America carries the OEM lower bumper stops, but not the uppers, and LMC does not carry either in OEM), go to your neighborhood salvage/junk yard and get them. Remember not to twist them off, but rather, push them out from the short-side to short-side (if this makes sense).

3. Polyurethane bumpers are fine as I found out today. I purchased another set of poly upper A-arm bumper stops since I tore one during my first installation, greased them to the cows came home, used a 10-inch "C" clamp which was guided/aligned with the help of my buddy, then compressed the clamp as far as it could go, and within 3 minutes, the bumper was properly seated (no damage whatsoever). Goes to show that we all learn from mistakes -- they are all educational experiences.

That's it for now. Installation of the front end commences tomorrow morning. More later.

[N2TRUX]

It's hard to disagree with your approach since you got the job done, but here's my thoughts. I assume using heat made them stops more pliable, but it also expanded them.

My bro-in-law who is a master mechanic showed me how he puts bushing in a freezer before installing them. The cold causes them to shrink, making them easier to press in place.

He does lube them with WD-40 to reduce friction.

[1986swb]

Originally Posted by N2TRUX

It's hard to disagree with your approach since you got the job done, but here's my thoughts. I assume using heat made them stops more pliable, but it also expanded them.

My bro-in-law who is a master mechanic showed me how he puts bushing in a freezer before installing them. The cold causes them to shrink, making them easier to press in place.

He does lube them with WD-40 to reduce friction.

Gosh. I wish I had your response sooner. But thanks for the insights. I would have tried the "cold" approach before the "heat" approach. I think less damage would have occurred.

Does the deep freeze work with both rubber and polyurethane? If so, I may just order another set of polys to replace the damaged upper A-arm ones. Yeah, I'm kinda a perfectionist.