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Rear axle - restoration
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MOTANUL  



Joined: 19 Nov 2018
Posts: 214
Location: ROMANIA BUCHAREST

PostPosted: Fri Feb 25, 2022 4:16 am    Post subject: Rear axle - restoration Reply with quote

Intend to restore Rear axle.
In order not to be without the car for a long time, I started to dismantle a 924 NA rear axle.
I saw that many parts are common only Rear axle carrier and Torsion bar differ. (931 / 924 NA).

The weak point of this rear axle are the large bushings on Rear axle strut: 477 511 201 / 477 511 202. The rest look great.

I intend to sand and paint the main components and order some spare parts.

What do you think of polyurethane powerflex bushings? (Powerflex Heritage / Black Series / normal - Road Series)



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Eliza  



Joined: 17 Aug 2015
Posts: 174
Location: Prov. Utrecht, The Netherlands

PostPosted: Tue Mar 01, 2022 12:30 am    Post subject: Reply with quote

I chickened out on the rear axle struts when I did my rear refresh on the n/a and bought two new ones from Partworks.

Seemingly the bushings are an absolute pain to get off, they were gulvanised in place by whoever made them. Paying for new seemed so much less hassle

Eliza
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MOTANUL  



Joined: 19 Nov 2018
Posts: 214
Location: ROMANIA BUCHAREST

PostPosted: Wed Mar 02, 2022 6:23 am    Post subject: Reply with quote

Eliza wrote:
were gulvanised in place by whoever made them. Eliza


Most likely they were installed in the factory 40 years ago and no one has touched them since.

Good to know! I'm definitely putting new bushings.

I thought the polyurethane (powerflex) are more resistant.
The rubber ones - Partworks - better for comfort.

I'll try to get one out and see how easy it is.
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 1227
Location: Maysville, Colorado

PostPosted: Mon Mar 07, 2022 2:36 am    Post subject: Reply with quote

The TB carrier castings are recognized as not a close tolerance part. I put the powerflex black(hard) bushings in my track car thinking they would be an easier fit than the solid delrin ones. It still took me about 6 hours of work to get them to fit well. Being rubbery the poly is quite hard to shape, the delrin would probably have been easier. Hopefully the normal blue ones are a bit softer and easier to fit. I believe I used a hacksaw, heat, a fish fillet knife and razor knives to get the old ones off.
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MOTANUL  



Joined: 19 Nov 2018
Posts: 214
Location: ROMANIA BUCHAREST

PostPosted: Wed Mar 09, 2022 10:31 pm    Post subject: Reply with quote

Very good to know. I really didn't think about this: polyurethane bushings won't fit TB carrier castings.
The truth is that powerflex are much harder and if the dimensions are not exact there is a good chance that they will not enter.

So blue ones or delrin from Partworks.

Ref. to get them out: cut them open. Wish me luck!


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MikeJinCO  



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PostPosted: Thu Mar 10, 2022 10:20 pm    Post subject: Reply with quote

I would expect the softer blue Powerflex would fit quite well. The delrin ones are known miserable to fit and I found the Powerflex Black not much easier. For a street car I would stay with the softer ones. I have taken my hard as possible bushing, 400 lb spring track car on a couple of short illegal road drives to see it it is running ok and it is a bone jarring experience, A one mile trip is plenty.
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safe  



Joined: 18 Mar 2017
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Location: Sweden

PostPosted: Thu Mar 10, 2022 11:35 pm    Post subject: Reply with quote

Consider getting new spring plates with stock rubber already fitted. A bit over €300 for a pair from rosepassion.
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MOTANUL  



Joined: 19 Nov 2018
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PostPosted: Wed Mar 16, 2022 4:07 am    Post subject: Reply with quote

safe wrote:
Consider getting new spring plates with stock rubber already fitted. A bit over €300 for a pair from rosepassion.


You scored this very well.
Although on the outside "Rear axle strut" looks very good - there was a lot of rust between the components.

Let's see how good it looks after blasting and cleaning. I haven't ordered anything yet.



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MOTANUL  



Joined: 19 Nov 2018
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PostPosted: Wed Mar 16, 2022 4:15 am    Post subject: Reply with quote

Eliza wrote:

Seemingly the bushings are an absolute pain to get off, they were gulvanised in place by whoever made them. Paying for new seemed so much less hassle
Eliza


I confirm that they did not come out easily - I think they were glued there from the beginning (glued on the inside and to be able to move on the outside).
For me the biggest problem was to get Torsion bar out of Rear axle strut.
On one side I could not get it out of any way. I put w40 and see if I can get it out on another occasion.
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safe  



Joined: 18 Mar 2017
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Location: Sweden

PostPosted: Wed Mar 16, 2022 4:22 am    Post subject: Reply with quote

MOTANUL wrote:
Eliza wrote:

Seemingly the bushings are an absolute pain to get off, they were gulvanised in place by whoever made them. Paying for new seemed so much less hassle
Eliza


I confirm that they did not come out easily - I think they were glued there from the beginning (glued on the inside and to be able to move on the outside).
For me, on the one hand, the biggest problem was to get Torsion bar out of Rear axle strut.
On one side I could not get it out of any way. I put w40 and see if I can get it out on another occasion.


Yank and hit the bar from side to side, that has helped me in the past.


The way to remove the rubber is to heat the inside of the steel with a propane torch and when the rubber starts to smoke you can twist them of easy by hand, if not more heat.
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MOTANUL  



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PostPosted: Fri Mar 18, 2022 6:45 am    Post subject: Reply with quote

Still stuck on one side (Torsion bar in Rear axle strut).

On the side where I managed to disassemble it - I continued with blasting.


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MOTANUL  



Joined: 19 Nov 2018
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Location: ROMANIA BUCHAREST

PostPosted: Sat Mar 19, 2022 6:01 am    Post subject: Reply with quote

I managed to get Torsion bar out of Rear axle strut.
1. Why didn't they put more grease in there? There was a lot of rust inside.

Ref. to rear axle strunt:
1. Those who put new bushings - did you glue them as they were the OE?
2. After the outer bush is a rubber area of a few centimeters. I will clean it. Does it have a purpose? Should it be redone or not?
3. Do you recommend galvanizing or electrostatic painting for rear axle strunt?


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MikeJinCO  



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PostPosted: Sat Mar 19, 2022 8:00 am    Post subject: Reply with quote

I have replaced bushings on two cars and never glued them on. Refinishing the spring plate sure looks good and probably helps if you live in an area where rust is common, no idea of expense. Don't understand what you mean about the other rubber.
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safe  



Joined: 18 Mar 2017
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PostPosted: Sat Mar 19, 2022 8:13 am    Post subject: Reply with quote

Bushings aren't glued or vulcanized from factory, they are just squeezed in really, really tight and after a while they get attached to the parts.
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safe  



Joined: 18 Mar 2017
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Location: Sweden

PostPosted: Sat Mar 19, 2022 8:16 am    Post subject: Reply with quote

MikeJinCO wrote:
Don't understand what you mean about the other rubber.


The part sticking out where the torsion bar ends, its covered in a rubber material of some sort. Maybe not every car but some years.
I dont think it has an important purpose. New spring plates are just zinkplated.
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