203 diff changeover

Wilko

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Fellow Frogger
Tadpole
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I have recently changed out my old diff on my 1951 203 to a 203C diff and the shock absorbers don’t line up. I think there are a couple of options - one is to swap the existing shocks with later 203 ones or second option is to make up some offset connecting links. As this problem has no doubt happened countless other times what might be the most often used remedy.
 
203 rear shock absorbers are the same for 203 and 203 C. There are left and right and the commercials have different arms.
 
I have recently changed out my old diff on my 1951 203 to a 203C diff and the shock absorbers don’t line up. I think there are a couple of options - one is to swap the existing shocks with later 203 ones or second option is to make up some offset connecting links. As this problem has no doubt happened countless other times what might be the most often used remedy.
Well the existing shock absorbers lined up with the old diff but not with the replacement 203 diff.
 
The shock absorbers line up with the axle housings. All 203 sedan axle housings in the parts books have the same dimensions as regard to shock absorber fixing points. Unless I'm reading them wrong. How much is it out by?
 
Last edited:
The shock absorbers line up with the axle housings. All 203 sedan axle housings in the parts books have the same dimensions as regard to shock absorber fixing points. Unless I'm reading them wrong. How much is it out by?
9F0BB793-9279-4207-B929-A5222A55B570.jpeg
Here
 
It's close. If you still have the old housings a few measurements might give a clue.
 
if there is no mis match or gap between axle and prop tube might it help to loosen or drop the rear engine mount?
 
I have recently changed out my old diff on my 1951 203 to a 203C diff and the shock absorbers don’t line up. I think there are a couple of options - one is to swap the existing shocks with later 203 ones or second option is to make up some offset connecting links. As this problem has no doubt happened countless other times what might be the most often used remedy.
What is odd is that the triangular bars and stabiliser/ panard rod line up ok so it seems that the shock absorber mounting eye on the trumpets are in a slightly different position.
 
Wilko,
I have nothing to offer with your situation, but I am interested to see how you solve it.
Cheers,
Dano
 
My "identification and classification drawing of spare parts in stock room" shows three different axle tube sets but the mounting holes in the same place.
 
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These are off the net hope it helps.
Did you only remove the centre case or dismantle complete rear end?
 
I have recently changed out my old diff on my 1951 203 to a 203C diff and the shock absorbers don’t line up. I think there are a couple of options - one is to swap the existing shocks with later 203 ones or second option is to make up some offset connecting links. As this problem has no doubt happened countless other times what might be the most often used remedy.
Both sides have the same offset - spoke to Malcolm Goodwin and he said he’d had that problem once and he got round it by loosening the shock absorber bolts and turning the shock enough to engage the bracket. I have bent an offset to the
connecting link bracket- have to do both ends to get the offset, otherwise the bracket contacts the side of the trumpet mount and side of the shock absorber - quite time consuming but should be ok.
405256D2-F8FA-4DAC-90FD-0461CC4494F7.jpeg
 
agree with mr goodwin - i reckon it's a question of geometry without loading - if enough is loosened to line up axle links. it would fall into place and permit re-tightening after the weight settles on the assembly
 
Had a similair issue when had to rebuild gearbox. When reinstalling rear end (panhard, shocks, springs etc) rear left shock did not line up with the coupling. I loosened the bolts on the shock, as suggested by Malcom, and had a friend push against the axle with his foot, towards the car, lining up the axle with the cupeling. Quickly slipped the bolt in and she was good. Once everything was tight, lowered the car and everything settled into place.
 

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