1800S rear suspension oddity

[Uplander]

Hi
I have a 1969 1800S with the 2 litre engine.
I'm in the process of replacing the rear suspension support arm with an already bushed replacement supplied by Brookhouse. However, the new arm is approx 20mm longer than the original so the mounting holes don't line up (430mm original, 450mm new). Both have the 'waisted' profile that take the waisted bushes.
I've spoken to Simon at Brookhouse and we're both in a bit of a quandary. He doesn't stock (or know of) a waisted arm 430mm long. There is an earlier support arm that looks the right length but takes the non waisted, cylindrical bushes which is not the correct arm for my model, but may fit. I've ordered one anyway to compare and I need to check what's on the other side but something's wrong...
Just wondering if anyone could throw some light on this?
Thanks
Simon

[Faust]

Just a quick couple of thoughts: have you got the axle under load? Are both sides of the car supported?

When I replaced my arms with new & polybushed the rear end of my Amazon, the only way I could get the big support arm in was to make sure the axle was under load (I only had one side of the car in the air as I was working at the side of the road which had a fair bit of camber and I didn’t think it wise to jack up both sides of the car).

This wouldn’t account for the 20mm difference in length you mention, but it might help.

Have you tried re-fitting the old arm? Does this go straight on or will it not fit?

If not, you might have the answer above.

Good luck.

[Uplander]

Thanks for your reply.
Initially I thought it was because the car was supported on one side only, but as you say 20 mm is a lot. I then compared the old arm with the new and discovered the size difference. The old arm still fits OK, but suffered some damage as one of the bolts was seized. I wasn't concerned at the time as I thought I had a replacement waiting. If I had to go back to an original I'd have to search for a used replacement.
I'd be interested to know, if anyone has a car of the same year, what length their support arm is so at least there's a starting point. Can't get my head round this one.
S

[Army]

May be some pictures will help the eagled eyed to come with a solution?

Is it possible that the original parts have been modified to lower ride height?

Which parts numbers did you order?

[Derek UK]

You would need to check this with Simon but the 140 used a similar arm which used the same bushes. The 1972 140 parts list has 3 different numbers for these arms and I believe that at some point the wheelbase was increased by a very small amount and this may have needed a longer arm. The 1973 parts list shows another part number and this may be the longer one. Brookhouse doesn't list these arms but advises to check according to chassis numbers. I'm thinking that if the arms are VERY similar you might have been sent a longer 140 arm. Even if Simon has stock for the 140 he might not have noticed the difference in length, if there is one.
1800 numbers for arms
671996
672616
140 to 1972
679451
686706
686729
140 - 1973
686257

[Uplander]

I'll post up some photos tomorrow Army. I ordered 672616 which is definitely the correct number for the date of the car and is the number on the side of the new part I ordered from Brookhouse.
Derek, thanks for the parts numbers insight, I'll investigate further. I really need to get confirmation of the length of the correct, listed part (672616) so I'll give Nordcar and Skandix a call and ask them to measure. Nordcar describes that part as "short type". Once I have confirmation of the length I'll know at least whether the part from Brookhouse is correct or not and I can then speak to Simon.
I'll be back with more info in due course.
Thanks

[Uplander]

I spoke to Nordcar in the Netherlands and they confirmed that part number 672616
was the correct part number for my car and that the support arm was 43cm long, the correct length.
I also contacted Skandix and they also confirmed that the part number was correct and that the slightly longer support arm is for the later 140.
Derek - you're thoughts on the matter would seem to be 100% correct.
So I'm presuming that Brookhouse have it wrong, i.e. the 1800S part number on the 140 part.
I've tried to call Simon today but I didn't manage to get through. I'll call Monday and see if they can work that one out.
The good news for me is that I can at least get the correct part from either Nordcar or Skandix if necessary, but hopefully Brookhouse can sort it out.
Thanks for your input.

Simon

[swedishandgerman]

I can't get under my '67 properly where it's currently parked to measure exactly, but it's about 43 centre of hole to centre of hole. Both arms the same.

[Uplander]

Thanks for measuring.
The old one I took off is 43cm end to end, not hole to hole, suggesting yours is longer.
Brookhouse have found an arm the correct size so I can get the car back on the road, but it seems a bit more investigation is required.
As a double check, if anyone has a 1969 1800S or later and has an opportunity to measure the arms in the near future I'd be grateful for the intel.
Thanks all for your assistance.
S

[jorzez]

I hope drawing with dimensions will help.
Measured from my P1800E 1970
I decided to use thicker tube 25x4 instead 25x2 mm (was completely corroded)and higher steel grade S355 instead standard S205.
workshop made it for ~55 GBP / pair
BL = blacha = plate
Ro = tube
szt. = pcs.