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front lower control arm bushing by jim94
Started on: 11-12-2019 09:00 PM
Replies: 16 (304 views)
Last post by: jim94 on 11-25-2019 01:47 AM
jim94
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Report this Post11-12-2019 09:00 PM Click Here to See the Profile for jim94Click Here to Email jim94Send a Private Message to jim94Reply w/QuoteDirect Link to This Post
i am changing my lower bushing because the bolt was rusted in and had to cut it out. so i removed the arm to look at the bushing and all the bushing look differant. my bushing in my car the metal center tube is smooth and the new ones are ribbed. i think the front lower bushings are not the right one, i mean like someone had put bushings that where ment for the top and put them on the bottom in the factory when new. the car is still stock, i am in the process of doing ball joints. my question is are the bushings the same on the front upper and lower. i did order new bushings from the fiero store and i hope thay fit. i have an 1987 gt
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Will
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Report this Post11-13-2019 09:38 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillReply w/QuoteDirect Link to This Post
All Fieros use the same front lower control arm bushings

These bushings are DIFFERENT between the forward and aft pivots on that control arm.

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theogre
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Report this Post11-13-2019 10:50 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreReply w/QuoteDirect Link to This Post
Yes, lower bushing set for Fiero and some others are different from Moog and likely others. See my Cave, Suspension Parts
OE ones are same for most years/models.

Moog part gives more rubber on rear so LCA doesn't move much when braking.

Inner "Tube" on all rubber ones are rolled steel w/ open seem and "Teeth" on ends as a locking feature.
See my Cave, Bushings how to remove w/o cutting class 10.9 bolts that are hard to get and cost more.

Solid inner sleeve w/o end "Teeth" are used in Polly and Polly have many issues used in control arms. They can wear out in a few years or less depending on how/where you drive and never make "polly noise."

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Blacktree
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Report this Post11-13-2019 02:23 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeReply w/QuoteDirect Link to This Post
To answer your question, the upper and lower control arm bushings are different. The lowers are much larger. So it would be impossible to accidentally install upper bushings in your lower control arm.

Also, as mentioned above, the front and rear bushings in the lower control arm are different. Be sure to get the right bushing in the right place. The upper control arm isn't like that. The upper bushings are all the same.
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jim94
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Report this Post11-13-2019 03:26 PM Click Here to See the Profile for jim94Click Here to Email jim94Send a Private Message to jim94Reply w/QuoteDirect Link to This Post
thanks for the information. when i get them i will fit them in place to see if thay fit. it should handle better with the right parts. i do understand how to install them.maybee my lower control arm will not hit the bump stop any more. this is m passenger side, the drivers side i bet has the right bushings because it never hits the bump stop. well back to work cleaning grease.
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theogre
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Report this Post11-13-2019 05:48 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreReply w/QuoteDirect Link to This Post
If car has been "lowered" then can kill 1 or both shocks and/or hit the bump stops constantly.
Even w/o that... In North America and other that drive right can do this for P side because that side is more likely to hit curbs etc. and break the shock/strut and more.

If P side is out, Both LCA are same but mirrored. Should match if you turn P side upside down to check it for bending etc.

Warning: When you replace bushings shocks etc then should replace both side of same "axle."
Very avoiding to dangerous things can happen if you fail to do this.

[This message has been edited by theogre (edited 11-13-2019).]

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jim94
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Report this Post11-14-2019 09:50 PM Click Here to See the Profile for jim94Click Here to Email jim94Send a Private Message to jim94Reply w/QuoteDirect Link to This Post
i went in the cave yesterday in the bushing section and it was right there. all the info i needed. the trailing bushing is not the same as the leading bushing. i am smarter now thanks for the info.
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pmbrunelle
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Report this Post11-18-2019 12:08 AM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleReply w/QuoteDirect Link to This Post
Hey Will, I seem to remember you had some insights as to why the lower A-arm bushing axes aren't aligned with each other.

Can you elaborate on that?
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Will
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Report this Post11-18-2019 08:39 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

Hey Will, I seem to remember you had some insights as to why the lower A-arm bushing axes aren't aligned with each other.

Can you elaborate on that?

 
quote
Originally posted by Will:
The thing I hate most about '84-'87 front control arms:



The other thing I hate most about '84-'87 front control arms:



The pivot axes are not aligned.

This makes using anything except sperical bearings a recipe for binding in one way or another. I wish I had known the design was that screwed up before I wasted hours on the lathe making UHMW bushings.



I don't recall that I ever had any insights as to *why*... just that that's the way it is, and it's sloppy design that GM got away with because they used rubber bushings.

Spacing the crossmember down from the body by an inch at the wheel centerline does wonders for brake dive, though.

[This message has been edited by Will (edited 11-18-2019).]

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pmbrunelle
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Report this Post11-18-2019 06:38 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:
I don't recall that I ever had any insights as to *why*... just that that's the way it is, and it's sloppy design that GM got away with because they used rubber bushings.


I was open to the hypothesis that it was done that way on purpose, to improve some aspect of the suspension that I don't understand.

Today, I asked my work colleague about the misaligned bushing axes (the other tire/suspension wizard I know of), and he had no explanations.

In the suspension rebuild of my 84-87 Fiero, I'm going to put poly mostly everywhere, except for the front lower A-arms, where the poly is too stiff and just binds.
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theogre
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Report this Post11-18-2019 10:21 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreReply w/QuoteDirect Link to This Post
If you look at the whole car...
The front and rear LCA bushing are mounted so bolts are not straight.
Example: Crash test video viewed from bottom. https://youtu.be/8y80ybh-eio?t=494

And unless your doing something wrong or car is damaged... the bolts will slide in the holes w/ little to no effort regardless of bushing material.

And Why are they "crooked???" This is likely to control Brake Reaction on the LCA.

WTF is Brake Reaction? Most have no clue because don't know or forget brakes put huge loads on front suspension and will compress all joints much different then normal driving or parked.
IOW When you brake, the "crooked" rear bushing and hardware keeps the LCA in good alignment and fights LCA twisting around a vertical point a lot more then UCA or Struts on most FWD/4WD cars. (Might see the opposite when floor the gas on FWD cars but same features helps there as well.)

Buick Riviera, Ford Mustang II, Pinto, Maverick and others had a big rod w/ big rubber bushings about where Rear LCA bushing is on many others and goes to a straight LCA between LBJ and frame.
Example:
CLICK FOR FULL SIZE

from https://www.hotrodders.com/...admaster-204963.html
Many doc's simple call them as a strut. Some others use the full name "Brake Reaction Rod."

Now watch same video and intimation the brake loads trying to twist and push the LCA back. That's on top of brake diving, brake while turning, etc. so just ignore them for now.
If you can, you'll get this faster then many others. I'm not 3d modeling this and most that do just ignore Brake Reaction issue.
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Will
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Report this Post11-19-2019 08:47 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

In the suspension rebuild of my 84-87 Fiero, I'm going to put poly mostly everywhere, except for the front lower A-arms, where the poly is too stiff and just binds.


I'm developing a spherical bearing kit for those pivots.
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Will
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Report this Post11-19-2019 08:51 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillReply w/QuoteDirect Link to This Post

Will

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quote
Originally posted by theogre:
Many doc's simple call them as a strut. Some others use the full name "Brake Reaction Rod."



Tension/Compression (T/C) rod is what I've heard them called.

While the bushings are angled, the angle is not very large from the point of view of putting brake loading perpendicular to the pivot bolt.

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pmbrunelle
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Report this Post11-19-2019 11:03 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleReply w/QuoteDirect Link to This Post
 
quote
Originally posted by theogre:
Now watch same video and intimation the brake loads trying to twist and push the LCA back. That's on top of brake diving, brake while turning, etc. so just ignore them for now.
If you can, you'll get this faster then many others. I'm not 3d modeling this and most that do just ignore Brake Reaction issue.


In the plan view during braking, I understand that the LCAs are being pushed back. As well, viewed from above, the LH LCA rotates counterclockwise, and the RH LCA rotates clockwise.

I just don't see how the relative misalignment between both bushings would help the situation any.
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pmbrunelle
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Report this Post11-19-2019 11:15 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:
While the bushings are angled, the angle is not very large from the point of view of putting brake loading perpendicular to the pivot bolt.


If that was the idea, it seems like a convoluted way of sort of barely loading the bushing more radially.

Looking at the video now, it looks like the forward pivots' bushing angles were determined by being perpendicular within the front subframe channel.

Then, the aft pivots were positioned in some desired spot.

Then, since the aft pivot position wasn't collinear with the forward pivot axis, a compromise angle for the aft pivot was chosen.

I think I'm going to roll with that hypothesis for now.
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Will
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Report this Post11-20-2019 08:32 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

If that was the idea, it seems like a convoluted way of sort of barely loading the bushing more radially.

Looking at the video now, it looks like the forward pivots' bushing angles were determined by being perpendicular within the front subframe channel.

Then, the aft pivots were positioned in some desired spot.

Then, since the aft pivot position wasn't collinear with the forward pivot axis, a compromise angle for the aft pivot was chosen.

I think I'm going to roll with that hypothesis for now.


All that happened at an Opel facility and was copy/paste into the Fiero.
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jim94
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Report this Post11-25-2019 01:47 AM Click Here to See the Profile for jim94Click Here to Email jim94Send a Private Message to jim94Reply w/QuoteDirect Link to This Post
My alignment is tuesday as i am done with my car.the lower bushings , both rear bolts where rusted in the bushing not the front. today was setup day for me, i had the tires on 5 " high ramps and went under the car to tighten the lower a-arm bolts and the lower shock bolt. wash tomorrow then prep for thanksgiving. it's time to fry the turkey. my fiero is new again. thanks for the help.
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