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Discussion Starter · #1 ·
I have just replaced the upper control arm bushings, and I forgot how the washers went on, since I took them apart bout 2 months ago. Anyway, I have the two thin washers...one against the head of the bolt, and the other the nut. Then I have thick washers, and thicker washers (about twice the size as the thick). The FSM shows these washers as being the same size. Is this true, or does the thicker one have to go on toawrds the front, or back.
 

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Old Opeler
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Caster Adjustment

The "thick" washers are Caster Adjustment Washers. The thickness of both washers must total 0.48 inches. 3 washers sizes are available: 0.12, 0.24 and 0.36 inches. Use an approved gauge to check the caster angle. Adjustment is effected by changing the thickness of these washers on BOTH sides of the upper control arm shaft.

To increase caster angle, fit one of the thin washers at the front of the shaft and one of the thick washers at the rear. Decrease the angle by fitting a thick washer at the front and a thin washer at the rear. Never use more than one washer at either location.

HTH
 

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Discussion Starter · #3 ·
OK, now I'm really confused. You're telling me that I have to buy (or get) a caster angle guage to put my UCA back on. To increase or decrease the angle..what is it supposed to be?? Thanks.
 

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Old Opeler
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Thick & Thin

The Caster angle is variously specified as 3 degrees + or - 1 degree (Opel FSM) and + 1 degree to + 4 degrees (Brookland Books OWM). Obviously the GT needs considerable postitive caster so as the manuals agree that: " To increase the caster place one of the thin ("thick") washers at the front of the conrtol arm shaft and one of the thicker ("thick") washers at the rear."

So it is a safe bet to put the thinner of the washers you have to the front and the thicker to the rear. When the GT is on its wheels again get a full front suspension geometry checkout at a professional wheel alignment shop to make sure everything falls inside the specifications - then blame me if it does not. No liability expressed or implied .....
 

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Discussion Starter · #6 ·
Thanks. I think that's how they came off. By looking closely at the washers, I can sorta tell the Thick washer was against the rubber bushing at the rear. Now on my parts car, where I took the control arms from, it used the same size washers (the medium sized) front and back. And as you said above, both combinations equaled up to be the .48 inches.
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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651 Posts
See my first picture and please advise if this is the correct configuration of the assembly of the upper control arm bolt, washers, etc.- I just disassembled the drivers side upper control arm and both of my washers appear to be, the same size, right and left - but it kind of fell apart and I cannot be sure exactly how to put it back together. I watched a video and could not tell exactly how to reassemble either - I also checked the service manual and as usual that was not very specific.
Please advise if this is correct. The first picture shows the following assemble as I think it should be:
Driver's side:
1. Nut facing the front of drivers side of car- left end cap that rests against the rubber bushing/metal sleeve-bushing through the arm- then thick rubber washer on the inside of control arm- then thick metal washer- then upright support behind the shock absorber - then thick metal washer- rubber washer- rubber bushing through the control arm- continuing rubber bushing - then end cap- head of bolt.

2. On a separate note: so I do not recall ever taking apart the upper control arms however I remember seeing the two items, in the picture to the right of the control arm in my misc. bolt/nut /screw/etc drawer for a lot of years and wondering what they were for - looks like an extra thick metal washer and an extra end cap, however compared to the ones on the bolt shown in the picture the extras look to be in a newer condition, not new but much newer looking: This really puzzles me as again I have been coming across those two items for years wondering what they were for. If you comment on the extra pieces remember they did not come off of the car when I took it apart this week....
3. The rubber bushings on this unit are in excellent condition so I do not intend to replace them - I was not expecting that. Removal and installation of both ball joints was easy.


429587
 

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Opel Rallier since 1977
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Looks right The thick, washers on the inside can be varied to move the UCA's position forward or back, to change the caster on the suspension. If they are the same thickness, then you are good to go.

The extra parts: Maybe there was an alignment done on this car in the far distant past, and these were taken out and different wahsers installed?

Good deal on the BJ's!
 
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