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-   -   Front Lower Control Arm Busing Removal (https://rennlist.com/forums/928-forum/987224-front-lower-control-arm-busing-removal.html)

Fresh 04-25-2017 08:05 PM

Front Lower Control Arm Busing Removal
 
Hi Guys, I need to remove the original rubber front lower control arm bushings. I have some purple powerflex poly bushings on the way. Would have probably gone with original, except the cost is just nuts. As it is, this restoration is moving at the speed of stink.

Anyhow, I looked for posts on doing the lowers, and also on youtube.com. Didn't find it. How does one get these old bushings out? Thanks in advance.

https://cimg6.ibsrv.net/gimg/rennlis...d693364238.jpg

Mark Anderson 04-25-2017 08:16 PM

I would think that the people selling the bushings would be able to tell you. I'm curious myself.

Hacker-Pschorr 04-25-2017 08:23 PM

Similar bushings on other cars I used a blowtorch to melt them out. I don't recall any of those suspension pieces being aluminum though.

Assuming you are going with the stiffer poly bushings in the rear location too? Be sure to follow the WSM procedure for torquing down those bolts so the suspension settles better. The hanging nose of the 928 will only be worse with stiffer bushings:


Volume IV
Page 40-5
Bolt #19

From the manual:
"Screw in until only 2 threads are visible. Do not tighten to 120Nm (88 fltb) until assembly is completed and springs have settled"

SeanR 04-25-2017 08:28 PM

Why do I think this is not going to turn out well?

worf928 04-25-2017 08:54 PM

:corn:

Fresh 04-25-2017 09:50 PM

Thanks
 
I was thinking the same thing: Melt the rubber out, unless there is a better way. I don't want to mess up the control arm. Gonna replace the front upper and lowers with the powerflex purple which I believe are 30% stiffer than stock. The black poly bushing are another story - 80% stiffer. It's just a street car, so that's overkill. Going to do the rear later. I hear than these newer polyurethane bushings do not squeak like some of the older ones. If it squeaks, I guess I'll just turn up the radio, right?

I think if I take anything else apart on this car (like the rear) I will seriously never get this car back together. Plus, I save to save for every new part so progress is so slow. I just want to get the car moving. It's been 10 years since it was on the road.

Hacker-Pschorr 04-25-2017 09:56 PM

We don't mean any ill will, just a lot of iffy opinions of using poly for suspension bushings.

Either way, just pay close attention to the above verbiage in the WSM, that is very important. Most suspension pieces you should physically hold at or close to "resting" before you torque the bolts down. That's a bit tricky with how these arms are designed and if you torque them down too far out of the center position, they may never properly settle.

Also your alignment will be more critical than most since the amount of time and effort it will take to "settle" will be longer than stock. This just reinforces the alignment procedure in the WSM where the shop doing the work sets & measures ride height by pulling down the nose instead of relying some some arbitrary mileage hoping the nose is fully settled.

Speedtoys 04-25-2017 10:05 PM


Originally Posted by Fresh (Post 14137437)
Hi Guys, I need to remove the original rubber front lower control arm bushings. I have some purple powerflex poly bushings on the way. Would have probably gone with original, except the cost is just nuts. As it is, this restoration is moving at the speed of stink.

Anyhow, I looked for posts on doing the lowers, and also on youtube.com. Didn't find it. How does one get these old bushings out? Thanks in advance.

https://cimg6.ibsrv.net/gimg/rennlis...d693364238.jpg

Why would you do this?

dr bob 04-25-2017 10:10 PM

The original bushings... Fronts are made-in-place for the most part, so the rubber flexes but doesn't actually move. I'm not sure how an aftermarket bushing material can be similarly made-in-place. Neither the aluminum control arm nor the aluminum support are ready for a bushing that slips.

In the rear, the bushing is bonded to the control arm and sits in a saddle between a formed section that's part of the crossmember, and the aluminum support. There is no provision for a slipping-style bushing. In fact, the factory recommends that you allow the suspension to settle some, before final tightening of that rear support clamp if the clamp is loose when the car is lifted on the suspension.

I'll be very interested is seeing what is actually supplied, and how the supplier recommends installation. :corn:

Speedtoys 04-25-2017 10:15 PM


Originally Posted by dr bob (Post 14137749)
The original bushings... Fronts are made-in-place for the most part, so the rubber flexes but doesn't actually move. I'm not sure how an aftermarket bushing material; can be similarly made-in-place. Neither the aluminum control arm nor the aluminum support are ready for a bushing that slips.

This is a huge misconception by..well, not to put a finger on the OP, but..people that buy a car and go off and change it, entirely against the principles that the car was designed under.

928 arm bushings are active SPRING RATE at work. I cant see a poly bushing working the same way.

Not just a dumb universal spacer allowing movement...and this is why aftermarket suppliers are just not stacked up providing these.

terry gt 04-25-2017 11:00 PM

the reason there is no info on bushing replacement is .... they are bonded in place .... not replaceable .
928 international has rebuilt units

slate blue 04-26-2017 07:21 AM


Originally Posted by Fresh (Post 14137703)
I was thinking the same thing: Melt the rubber out, unless there is a better way. I don't want to mess up the control arm. Gonna replace the front upper and lowers with the powerflex purple which I believe are 30% stiffer than stock. The black poly bushing are another story - 80% stiffer. It's just a street car, so that's overkill. Going to do the rear later. I hear than these newer polyurethane bushings do not squeak like some of the older ones. If it squeaks, I guess I'll just turn up the radio, right?

I think if I take anything else apart on this car (like the rear) I will seriously never get this car back together. Plus, I save to save for every new part so progress is so slow. I just want to get the car moving. It's been 10 years since it was on the road.

Just use a press to push the bushings out. That is what I did and no damage at all. If I get time I will post some pictures. Where did you buy the Powerflex bushes?

Cheburator 04-26-2017 12:08 PM

Don't buy the powerflex bushings! I repeat - don't buy poly bushes. My best man, who is also on here - drnick - did it and within 3yrs they were FUBARed...

It has already been said - the original bushes are part of the spring-shock combo and work very well.

There are two-known sources for replacement - Mark Anderson's rebuilt arms, which by the way are superb, and Rosepassion in France, who would sell you the rubber bushes, but you would have to figure out how to bond it to the arms.

FredR 04-26-2017 02:03 PM


Originally Posted by dr bob (Post 14137749)
The original bushings... Fronts are made-in-place for the most part, so the rubber flexes but doesn't actually move. I'm not sure how an aftermarket bushing material can be similarly made-in-place. Neither the aluminum control arm nor the aluminum support are ready for a bushing that slips.

In the rear, the bushing is bonded to the control arm and sits in a saddle between a formed section that's part of the crossmember, and the aluminum support. There is no provision for a slipping-style bushing. In fact, the factory recommends that you allow the suspension to settle some, before final tightening of that rear support clamp if the clamp is loose when the car is lifted on the suspension.

I'll be very interested is seeing what is actually supplied, and how the supplier recommends installation. :corn:

The bushes at both ends are a push fit installation and each end has an inner bush and an outer bush separated by a concentric stainless steel spacer. The installation sequence is listed being critical to success.

I was thinking of going this route when I found my driver side LCA [I was using the earlier longer arm/bracket to get more camber on that side] looked shot [I did a thread on this]. Instead I reverted back to the stock arm recently and was surprised when I managed to get it to 1.7 degrees [previously it was just over 1 degree or so the Hunter said] so no need at the moment.

I was intrigued as to how these bushes work compared to the stock items and I suspect some of the judgements here may be a bit hasty. I figured that the Powerflex design might be intended to allow some slip but more likely the concentric steel spacer locks onto the inner eurethane bush when the assembly is pressed onto the hub and the outer eurethane bush is locked to the inner spacer by the external clamp/bracket. How this impacts overall suspension movement in terms of stiffness remains to be seen but I get the impression this outfit may well know what they are doing if their CV is anything to go by.

Needs someone like Mark K to give them a good shakedown [ assuming his "vacation" is nearly over?].

slate blue 04-26-2017 05:22 PM


Originally Posted by Cheburator (Post 14138908)
Don't buy the powerflex bushings! I repeat - don't buy poly bushes. My best man, who is also on here - drnick - did it and within 3yrs they were FUBARed...

It has already been said - the original bushes are part of the spring-shock combo and work very well.

There are two-known sources for replacement - Mark Anderson's rebuilt arms, which by the way are superb, and Rosepassion in France, who would sell you the rubber bushes, but you would have to figure out how to bond it to the arms.

Alex, Powerflex bushes, the street versions come with a lifetime warranty, the race versions don't. These bushes are three piece designs and have been revised recently. Did Nick's bushes come from Powerflex? I know there was two piece designs around before by other sellers that of course won't last. The discussion I had with Powerflex was that the main reason behind the three piece design is because the arm's spigot is not a machined part as such it's needs an adaptation to a machined surface and this also allows for the variation in bushing stiffness.

As to the bushes forming part of the spring rate, I think we all know they shouldn't be performing that function. I think we all are aware that as our cars have aged various wear parts have changed our car's feel. Some examples are, damper valves, bushes, and seat bases.


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