Strange 88 rack issue (Page 1/3)
watts MAY 13, 10:46 PM
Working on a fairly low mileage 88. ~65K miles.

Everyone and their dog knows about the r/h rack bushing (this one is tight), but this one seems to have issues on the left hand side!
Moving the rack back/forth gets you a rapid thumping, as the teeth of the rack rumble against a steel collar inside.

The bearings on the input pinion shaft are perfect. I can't see wear on the pinion gear.

Looked at the parts breakdown in the manual, nothing appears to be missing. What am I not seeing??

Thx.
watts MAY 13, 10:56 PM
Just to be clear, I've got the rack removed, mounted in my vice!
theogre MAY 14, 10:20 AM
Miles don't matter...
The suspension and thus the rack maybe hit something on left side.
May need to pull the unit apart.
Also may need to look very hard at rest of left side.
Big potholes etc can damage one side w/o obvious damage to rest of car.
Can bend more of left side or not because CA have rubber to protect them unless hits a large thing and rubber can't take total impact.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

watts MAY 14, 10:33 AM
It's mounted in my vise. It's been 100% taken apart, parts all cleaned and lubed.
Sorry, thought the dismantled part was implied.

I've got the car on my hoist. There is no damage to anything else.

I've been working on P-bodies for over 20 years, and this is the first time I've seen this - of course, most of those were early cars.
reinhart MAY 15, 05:43 AM
Did you change both upper and lower pinion bearings? Whether they "look" ok doesn't matter. If the bearings aren't turning freely then it can cause drag and other issues.
watts MAY 15, 10:14 AM
They look ok, as they are ok. I've removed, cleaned, tested, re-lubed and reinstalled.

To be clear... I'm a licensed mechanic, this is not my first rodeo.
I've just never encountered this issue on an 88 rack.

Does anyone have one apart right now? Can you look down the drivers (left) hole, and measure the ID of the steel collar in there?
Is there a sleeve/bushing/something that just isn't there on this one? What I'm hearing is the teeth of the rack rumbling across that steel collar.
Mark_j MAY 15, 09:59 PM

quote
Originally posted by watts:


Looked at the parts breakdown in the manual, nothing appears to be missing. What am I not seeing??

Thx.



Have you checked the run out of the tie rods and the rack itself? If it sounds like the teeth are rubbing the guide ring I would check to see if the rack hasn't been tweeked slightly.
watts MAY 16, 07:26 PM
Checked the main rack, and it's dead straight in 2 axis - so no bend at all.

But!
The rack itself is 21.96mm diameter (very consistent end to end, and again in 2 axis).
The collar/bushing (on the left, not the plastic r/h one!) has an ID of 23.25mm - again, very consistently. So if it's wear, it's done a great job of it.



Ignoring that this a PS rack - position premise is the same:

[This message has been edited by watts (edited 05-16-2021).]

watts MAY 16, 07:31 PM
And speaking of the above power rack - the GM parts site I grabbed that from, seems to think that it's for an '88 Fiero!
As well as a 2 years of Bonneville.



I'm sure someone's tested THAT theory over the years!
watts MAY 19, 08:52 PM
So yeah, that is a separate sintered iron (that's what it feels like anyhow) bushing.
Heated up the end of the rack, and a few taps later it was out.

Just because it's easier than searching forever, guess I'll make a new one.

I mean, they don't even have a number on any drawings I've found associated with it!
So to buy one is probably right out.

Thinking 932 Bronze?