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??
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)
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.
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.
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.
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).]
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!
I thought there was someone that had modelled the whole rack, was hoping he'd see this and chime in.
Bushing was for sure not aluminum. Totally looked, felt, and weighed about what powdered metal would be. Was stupid busy at work and didn't get a chance to call around to find some material. Hopefully tomorrow so I can get it done over the long.
I'd be inclined to think that the issue would be with the bearings for the input shaft since it seems to be on the left side. It's common for them to deteriorate from what I've heard.... Rodney Dickman sells them, they're pretty cheap and they go in easy; I replaced them when I overhauled my suspension a few years ago. https://rodneydickman.com/p...php?products_id=370. If everything looks good suspension wise like you're saying it is, I'd rebuild the rack with some new bearings and a bunch of high quality grease as well as the brass bushing on the right side... Though it couldn't hurt to replace the ball joints and tie rods while everything is apart. Low miles or not I'd do it anyway due to age, honestly!
------------------ "Discord" Red 1988 GT under restoration!
Originally posted by reinhart: You said the ID of the original one was 23.25mm. What's the ID of the one you fabricated?
How did you get the original one out?
OD of the rack itself is 21.96-22.00, so I made xxx.
There's a small clearance area on the inside, just (!) big enough to get a hook behind. Heated the rack end to let it swell, and with a slide hammer got it out. There are inside bearing pullers that would have worked better, but I don't have anything the right size/shape.
-
There isn't enough (built in slop?) to let the input pinion go back in correctly. I'm going to have to sneak up on it to find the happy spot. Sure be nice if someone with a good working rack had taken these measurements... sigh... A sample size of ONE does not good data make! Heh.
[This message has been edited by watts (edited 05-24-2021).]
Nice work! Wish I could fabricate... well, anything.
quote
Originally posted by watts:
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!
First time I've ever heard that! But wouldn't that be a b!tch, after all these years?
Edit - Of course I had to check. Obviously a mistake. W-body has the rack behind the wheels. Turns the wrong way.
[This message has been edited by Raydar (edited 05-24-2021).]
F'n 'ell. This whole bushing has been a red herring it looks like. I'm wiping a lot of my posts above so nobody gets thrown off in the future.
It makes no difference if it's in or out!!! Exact same noise. Watch this: https://youtu.be/sjTRVDYVLBM I pushed the bushing in slightly, so it would "fall out" part way through the stroke as you'll see.
I have zero idea what now, but it seems to (?!) have something to do with the gear engagement itself. Makes no difference if it's the far left, or far right, or center of the rack. Each tooth of the input pinion makes the same noise. I've tried sliding it in/out to change the engagement spot. Same.
Done it with, without the preload.
I hate to throw in the towel and just say replace it, but... there just aren't enough to compare to, to find the actual issue.
F'n 'ell. This whole bushing has been a red herring it looks like. I'm wiping a lot of my posts above so nobody gets thrown off in the future.
It makes no difference if it's in or out!!! Exact same noise. Watch this: https://youtu.be/sjTRVDYVLBM I pushed the bushing in slightly, so it would "fall out" part way through the stroke as you'll see.
I have zero idea what now, but it seems to (?!) have something to do with the gear engagement itself. Makes no difference if it's the far left, or far right, or center of the rack. Each tooth of the input pinion makes the same noise. I've tried sliding it in/out to change the engagement spot. Same.
Done it with, without the preload.
I hate to throw in the towel and just say replace it, but... there just aren't enough to compare to, to find the actual issue.
Watts, I'd just get another 88 rack. If you really look, you can get one.
