Mystery pop

A place for all technical questions.
Post a reply

Mystery pop

Postby critter » Sun Oct 17, 2010 5:35 pm

I as out for more of an extended drive this afternoon. My goodness, what a difference having the front suspension reworked and adding low profile tires on bigger wheels has made. This thing sticks its nose into a turn and it feels like it's just dragging me and the rear end along for the ride.

But, there's always a but, I now notice that the occasional "pop" I'd get from the rear end is doing it in every turn that I take with speed. I suspect that it's due to worn out suspension back there and I have new springs/shackles on order but I'm curious if there might be another cause. Anyone ever experience anything like this before? Opinions on what might be causing my pop? Whatever it is is physical because I can feel it through the floor when it happens.

FYI, at the suggestion of Mary Pozzi, I pulled the rear sway bar a while back and the pop is still there so it's not that.

1974 Trans Am
8.5 inch rear end with 3.42 gears (formerly 3.08)
Converted drums to Pontiac/Caddy rear disk
All bushing are polygraphite (I know, but back then eveyone said do it...)
CE subframe connectors, welded at the front, bolt in at front spring eye in the back.
User avatar
critter
Chief
 
Posts: 5408
Joined: Mon Sep 27, 2004 8:36 pm
Location: Maumelle, Arkansas
Top

Re: Mystery pop

Postby JAA » Sun Oct 17, 2010 8:49 pm

If you can feel it in the floor, I wonder if it is the subframe connectors. Maybe either a loose bolt or a weld that has cracked.
JAA
 
Posts: 4
Joined: Thu Oct 07, 2010 11:51 am
Top

Re: Mystery pop

Postby RamAirDave » Sun Oct 17, 2010 9:01 pm

critter wrote:All bushing are polygraphite (I know, but back then eveyone said do it...)


Don't like the PG?

I don't know, but there aren't a whole lotta parts back there to check. Obviously make sure all is tight and that no bushings are just flat worn out. Maybe check the exhaust also. Now that the car is gripping better, other stuff may be movin' around and under more stress than before?
69 GTO RAIII 4spd, 70 Z28 RS



"Build them how the designers and engineers envisioned them to be" MCG

Driving #s/paper cars in the rain... and lovin' it punkr
User avatar
RamAirDave
Chief
 
Posts: 699
Joined: Wed Sep 29, 2004 8:58 pm
Location: NLR
  • Website
Top

Re: Mystery pop

Postby critter » Mon Oct 18, 2010 10:36 am

I'm going to crawl under there Tuesday night and do some poking around. I have to be out of town this evening so no sleuthing tonight. I suspect I'm going to find that it's tied to the rear suspension being worn out just like the front was.
User avatar
critter
Chief
 
Posts: 5408
Joined: Mon Sep 27, 2004 8:36 pm
Location: Maumelle, Arkansas
Top

Re: Mystery pop

Postby critter » Tue Oct 19, 2010 8:19 pm

I may have found it. One of the three bolts that hold the front spring eye pocket to the body spun freely when I checked it for tightness. This is also one of the 2 mounting bolts for the CE subframe connectors I installed umpteen years ago. Looking at the wear marks it appears that loose bolt was allowing the subframe connector to twist and move. I Helicoiled it and will try to get it to pull tight tomorrow night after the Loc-tite has seasoned. If not, Mr. Welder may get the call.
User avatar
critter
Chief
 
Posts: 5408
Joined: Mon Sep 27, 2004 8:36 pm
Location: Maumelle, Arkansas
Top

Re: Mystery pop

Postby RamAirDave » Tue Oct 19, 2010 8:25 pm

Does a 2nd gen use a clip nut like the 1st gens, or are they "in" the body? They are notorious for breaking on the early cars.
69 GTO RAIII 4spd, 70 Z28 RS



"Build them how the designers and engineers envisioned them to be" MCG

Driving #s/paper cars in the rain... and lovin' it punkr
User avatar
RamAirDave
Chief
 
Posts: 699
Joined: Wed Sep 29, 2004 8:58 pm
Location: NLR
  • Website
Top

Re: Mystery pop

Postby critter » Tue Oct 19, 2010 8:33 pm

This one is a threaded hole in the frame rail. It's stripped out. I'm thinking s nut-sert might be in order once the new springs arrive. They are ordered but it will be a week or 2 before I get to it.
User avatar
critter
Chief
 
Posts: 5408
Joined: Mon Sep 27, 2004 8:36 pm
Location: Maumelle, Arkansas
Top

Re: Mystery pop

Postby RamAirDave » Tue Oct 19, 2010 9:08 pm

We have the tool to install nut-serts, but don't have any that are that large of size. We can probably get 'em though, if ya need any help on it. :happy:
69 GTO RAIII 4spd, 70 Z28 RS



"Build them how the designers and engineers envisioned them to be" MCG

Driving #s/paper cars in the rain... and lovin' it punkr
User avatar
RamAirDave
Chief
 
Posts: 699
Joined: Wed Sep 29, 2004 8:58 pm
Location: NLR
  • Website
Top

Re: Mystery pop

Postby critter » Tue Oct 19, 2010 9:18 pm

10-4. I used a Big-Sert on the block that time I stripped out the hole torquing the head bolt. I'm sold on those things. I might be looking at their products to see what's available. Those things are tough as nails.
User avatar
critter
Chief
 
Posts: 5408
Joined: Mon Sep 27, 2004 8:36 pm
Location: Maumelle, Arkansas
Top

Re: Mystery pop

Postby JAA » Tue Oct 19, 2010 9:25 pm

Glad you may have found it. Nothing worse than an unknown noise that bugs you while you are
driving... confused2
JAA
 
Posts: 4
Joined: Thu Oct 07, 2010 11:51 am
Top


Post a reply

Return to The Shop

Who is online

Users browsing this forum: No registered users and 1 guest

cron