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Rear Subframe Rebuild

6810 Views 114 Replies 12 Participants Last post by  Leebluegtv
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Since getting the Spider about 5 years ago, I’ve been slowly collecting the bits I need to rebuild the rear suspension which I started today. I thought I’d document the progress on here adding to the thread as and when I do something. I’ve decided to go down the route of rebuilding a complete subframe and fitting it to the car rather than swapping parts in situ so the car will be off the road for the minimum amount of time.

First of all the parts you need. I’ve got the following…

Spring pans
V6 ARB and Powerflex bushes
Dog legs
Wheel bearings
Hubs
Refurbed brake calipers
Powerflex bushes
Brake hoses
Brake compensator
Subframe
Various nuts, bolts and washers etc
Eibach springs
Drop links
Ball joints
Brackets for handbrake cables, brake hoses, exhaust hangers etc

I’ll add to this list if I think of anything else I need

Still to buy…

Rear shocks
Rear discs
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Nice work… you’re a bit ahead of me but I’ll hopefully catch up a bit as mine only needs moving a couple of yards from the garage to the car. What bushes did you use? They look like Powerflex so any tips on getting them in?
The bushes were done by a previous owner (thank you whoever it was, you saved me £££) and are a mixture of black/purple polyurethane, which I assume must be Powerflex. Easy to install with a bit of bush lube (snigger). I only needed a 10g sachet to do the lot. You aren't that far behind, all the above was a couple of hours work. Nothing is tight yet, as I will do that once it is all weighted up.

Not sure about how I am going to get the springs/hubs on yet. Hoping my spring compressors will fit...
 

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Malc, I got my rear spring in place without any spring compressors. The spring are so short they are not needed, you just need someone to help get some weight on them to to line up the bolts. I did actually buy some spring compressors for the job but found that because the spring are so short they would not work as needed.
 

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Discussion Starter · #23 ·
Powerflex are super easy to get into the holes in the arms, a little silicone grease and they all push in by hand. The struggle (on a V6) is getting the bushes at the hub end all lined up, particularly the powerflex washers. V6 springs are longer and need a fair bit of compression to get the rear arms lined up, on the TS it is much, much easier as the spring is barely under any compression. I used an old long hub bolt, tapered the end then rounded the point, and inserted it the wrong way through the hub to line up the bushes, then fed the new bolt the correct way, hence pushing the alignment bolt out. This made sure the bushes, washers and hub were all in alignment. The bushes themselves don't pivot like factory items, so when the arms are past the natural position they sit in with the weight of the car, there is a fair amount of tension caused by the misalignment of the bushes (the sleeves are forced out of parallel in the bush) which can be a struggle. I have fitted them on a TS and V6 (both times subframe on the car), much much easier on the TS but still takes some fiddling.
Thanks… I’ll give it a go once I’ve cleaned up the insides of the various holes that need bushing
The bushes were done by a previous owner (thank you whoever it was, you saved me £££) and are a mixture of black/purple polyurethane, which I assume must be Powerflex. Easy to install with a bit of bush lube (snigger). I only needed a 10g sachet to do the lot. You aren't that far behind, all the above was a couple of hours work. Nothing is tight yet, as I will do that once it is all weighted up.

Not sure about how I am going to get the springs/hubs on yet. Hoping my spring compressors will fit...
Thanks… I’ve changed the spring on the car and didn’t need a spring compressor at all. The weight of the car holds them under sufficient compression to stay in place. Undoing one end of the spring pans was all that was needed to get the old spring out and a bit of help from a jack to get it back together.
 

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Forgot to say that I put the spring in place with the subframe off the car, so if the frame is on the car then should a matter of just jacking the spring pan. Also I used OE spec bushes which give you extra movement in the arm, so not sure if that helped me at all.
 

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Discussion Starter · #26 · (Edited)
Wishbones (continued)

Got a bit more done on the subframe over the last few days… I finished cleaning out the holes for the bushes with various bits of wet & dry, flap wheels etc. There was a bit of pitting from corrosion which I’m guessing is from water ingress with the old bushes so I applied a bit of Kurust, let it dry and sanded again. I put the bushes in by covering everything in plenty of the grease that comes with the bushes then pushed them in using a couple of large washers and a bolt which I tightened to push then in.
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This method seemed to work and they went in no problem so I repeated with the stainless steel tubes and they went in fine… and that’s when the problems started. With the tubes in the bushes out of the wishbone, the bush and tube are the same length which is 30.5mm according to my caliper.
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Which makes sense as the gap in the subframe is 30.4mm so it should be a snug fit.
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Once I’d put the bushes and tubes in, the bushes seem to have lengthened as they’re squeezed into wishbones so they measure 34.3mm and won’t fit in the subframe. I’ve tried to persuade them in with a rubber mallet but they just ain’t going in and all I’ve achieved is chipping some of the paint. Any suggestions? I’m going to try squashing them in with a vice at work tomorrow. I don’t really want to file them down as they should fit but how?
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I found the upper wishbones the most difficult to get in... it needs a bit of wiggling and persuasion and trying at different jaunty angles and eventually it slid in with relatively little difficulty. I am reusing older poly bushes though. Bit of bush lube on the outer surfaces will help.

edit: although looking again... yeah, that seems way off. Got the right tubes in there? 🤷‍♂️
 

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Discussion Starter · #28 ·
The tubes fit perfectly in the space in the subframe. Out of the wishbones, the bush and tube also fit perfectly. It’s just when it’s put in the wishbones they seem to get longer. I’ve put them in a big vice at work today and squash sufficiently to fit so hopefully the bushes will have softened up a bit and will fit.
 

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I'm not sure mine were that far out, but I do recall having some fun getting some of the arms back into the gaps in the subframe. Make sure you insert the arms the right way round too - they are sided(!) and it's also a PITA if you fit them upside down (sadly speaking from experience).

As above, used lots of lube and some creative nylon malleting. Worth it in the end, was a treasure to drive until corrosion got the underfloor...
 

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Discussion Starter · #30 ·
I’ve had a go at getting them in and although I couldn’t get them in, I’ve made progress they still ain’t going in. I’m wondering if a bit of gentle heat will soften the bushes to help get them in.
 

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Useful thread. This is something I will need to do at some stage.

Once finished will be interested to know difference in handling with the V6 rear ARB. I have a new one in stock from Partsworld and the diameter is significantly larger than the TS/JTS version.
I did swap the 18mm TS/12V ARB for the 24V 21mm version: noticed no difference at all!

It should make a difference of course, it is 59% stronger! 🤷🏼‍♂️

So maybe one day I will try the Dutch made 25mm version which is 2,7x stronger than the 18mm: www.la-mosca.com


I have also a 23mm front ARB (from 155 V6) on the shelf which is 52% stronger than the 20mm which is OEM. But this has to wait till I have the 6-speed gearbox with Q2 ready...
 

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Discussion Starter · #32 ·
Still having trouble getting the wishbones in. They have taken a serious battering trying to hammer them in but they just ain’t going in… and need repainting now.
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Still having trouble getting the wishbones in. They have taken a serious battering trying to hammer them in but they just ain’t going in… and need repainting now.
View attachment 980141 View attachment 980142 View attachment 980143
Not wanting to state the obvious, that's not going to fit. When I had mine fitted they were the 'purple' version, which I believe is no longer available. These were a tight fit as well, I remember the specialist needed to adjust them a little bit for them to fit. It may be the 'black' version is more difficult to fit possibly due to:
1) the black version is much harder than the purple version and so less forgiving
2) A small adjustment may also be needed.

Either that, or you could try superflex, which may be a better fit:

www.superflex.co.uk/proddetail.php?prod=SF430-0346KSS

I wouldn't force them though. You don't want to break the retaining bracket!

EDIT: Looking at your photos again. On the side that does not have the large outer sleeve. When I looked at my upper wishbones the other week that side is almost flush with the inside of the bracket. So my specialist must have adjusted the thickness here for them to fit. I wouldn't see any harm adjusting this side of the bush for the arm to fit.
 

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I did swap the 18mm TS/12V ARB for the 24V 21mm version: noticed no difference at all!

It should make a difference of course, it is 59% stronger! 🤷🏼‍♂️

So maybe one day I will try the Dutch made 25mm version which is 2,7x stronger than the 18mm: www.la-mosca.com


I have also a 23mm front ARB (from 155 V6) on the shelf which is 52% stronger than the 20mm which is OEM. But this has to wait till I have the 6-speed gearbox with Q2 ready...
Thanks for that. Interesting there is no difference! I might try it anyway, if only because my TS rear ARB is a bit rusty.
 

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I the issue of the actual metal bush being too long to fit into the subframe when I did my one using purple powerflex ones, the ploy bit itself was fine. In the end had to get powerflex to machine a set of new one for me and they worked fine, not the same issue as you but just saying that there seems to be many issues with these bushes ?
 

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Discussion Starter · #36 ·
Not wanting to state the obvious, that's not going to fit. When I had mine fitted they were the 'purple' version, which I believe is no longer available. These were a tight fit as well, I remember the specialist needed to adjust them a little bit for them to fit. It may be the 'black' version is more difficult to fit possibly due to:
1) the black version is much harder than the purple version and so less forgiving
2) A small adjustment may also be needed.

Either that, or you could try superflex, which may be a better fit:

www.superflex.co.uk/proddetail.php?prod=SF430-0346KSS

I wouldn't force them though. You don't want to break the retaining bracket!

EDIT: Looking at your photos again. On the side that does not have the large outer sleeve. When I looked at my upper wishbones the other week that side is almost flush with the inside of the bracket. So my specialist must have adjusted the thickness here for them to fit. I wouldn't see any harm adjusting this side of the bush for the arm to fit.
I’ve messaged Powerflex so I’ll see what they say. I am tempted to try Strongflex. Adjusting them would very much be a last resort as they should fit without modification.
I the issue of the actual metal bush being too long to fit into the subframe when I did my one using purple powerflex ones, the ploy bit itself was fine. In the end had to get powerflex to machine a set of new one for me and they worked fine, not the same issue as you but just saying that there seems to be many issues with these bushes ?
Since I’ve started looking for any advice on fitting them, I’ve come across a number of posts where people have had issues. The metal part seems the one bit that is actually the right size. Out of the wishbone, the rubber bush is also the right size and fits snuggly in the subframe but because it is slightly larger in diameter than the hole, one it is in the wishbone, it is squashed in diameter causing it to get longer (if that makes sense).
 

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Hmmm, i had troubles with the top wish bone black poly bushes, but not as bad as yours. Yours just don't look right. Get powerflex to send new set... Yours just don't look like the right part. Mine were a struggle on v6 and jts but nothing like the troubles you are experiencing. Maybe twinnie wishbones are different??? I would go back to the biggining and research again... 🍀🍀🍀🍀
 

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Discussion Starter · #38 ·
Can anyone confirm what size the holes in the wishbones should be? I have had a good look at mine and it doesn’t look like there are any bits of the old bushes left in but that is one possibility and would explain the 2-3mm difference between the bushes and the hole.
 

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Good point actually - all my rear end was superflex (or modified spherical bearings on I think the dogs (can't recall) so that may have helped.
 
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