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Discussion Starter · #1 ·
Is it essential or advisable or unnecessary to do an alignment after removing and replacing the front cross member on an 1800S? This would be putting the same cross member back in place after lowering it to do something like remove an oil pan.
 

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Is it essential or advisable or unnecessary to do an alignment after removing and replacing the front cross member on an 1800S? This would be putting the same cross member back in place after lowering it to do something like remove an oil pan.
Did you remove, mark, save the shims and replace them in the same place? Regardless, things might be slightly different when reinstalled. It would be prudent to have the alignment checked and corrected if necessary.
 

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Discussion Starter · #3 ·
Hypothetical question at this point. No plan to disassemble anything that adjusts alignment, just lower it enough to pull the oil pan to get at the oil pump. However, I agree that it would be wise to have the alignment checked afterward.

I haven't done it before. From reading about the procedure I think it would require supporting the engine, disconnecting the engine and transmission mounts, replacing two bolts with longer ones, supporting the engine with a jack, removing the front wheels, removing remaining bolts and easing the engine down onto the two long bolts.
 

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I have not done that on a P 1800; but, I have done it on my 142 E


As a related note, it is not really possible to support the engine on a jack if you want to remove the pan. The front lip of the pan is the normal jacking point when you are doing things like engine mount replacement. Hence the need for the special Volvo tool or a Rube Goldberg collection of 2x4s to lift / support the engine. On the 140, I did not touch the transmission mount as it establishes the pivot point when lifting the engine. You may want to check the transmission mount after the lift because they don't deal well with a lot of shear load, particularly the after market ones which seem to separate if you look at them hard.

On the 140, if all you do is drop the cross member, you do not alter the camber or caster adjustments because those are all established by the shims on the upper A arm attachment. On the 1800, as I recall there are two caster adjustments. Shims under the cross member mounting bolt and shims on the upper A arm. You should not have to touch the Upper A arm attachment and as long as you don't lose the caster adjustment shims between the cross member and the body channel your caster settings should remain OK on re assembly. On the 140, the way the cross member bolts to the body channels it is possible to get the cross member mounted so that it is not exactly 90 deg to the vehicle center line. On the 1800, it appears that there are horizontal mounting bolts for the cross member which may effectively constrain this 'out of adjustment problem'.

Once the car is bolted back together and on the ground it would be possible to use a string line to check deviations between the front and back wheels in terms of the direction they are pointed in which may be caused by how the cross member is mounted. Alignment shims will not fix that problem. You need to loosen stuff and shove the cross member around if you want to get it perfect. A good alignment specialist collision restoration shop can put the car on a jig and tell you whether the front cross member is 90 deg to the car center line. Getting them to loosen stuff and tweak it could get time consuming / expensive. If you go to one of those muffler / tire / alignment / oil change places they tend to be roll it on, fiddle with the shims roll it off and are unlikely to fix a mounting problem.
 

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Discussion Starter · #5 · (Edited)
Yes, I meant and should have said "supporting the cross member with a jack" - not the engine. I also should have said easing the cross member down, not the engine.

The engine would best be supported from above. I think the two long bolts should stabilize the cross member well enough to just use a floor jack at the center of the cross member to support it and ease it down on the two long bolts.

You're probably right about the transmission mount too. If the engine is supported from above, it shouldn't move enough to require loosening the trans mount.

Oh yes, I'd have to disconnect the sway bar and steering arm.
 

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I used to lower front ends often in the late '70s on 1800's, 122's and 140 series cars when I worked part time in a Volvo repair shop. We used fairly firm foam rubber strips on top of clean soft felt strips after cleaning the paint on top of both fenders, under two 2 x 4's a foot and a half long (lenghtwise to spread the weight out) on top of the fenders. A 4 x 4 was used on top of the 2 x 4's across the engine bay and the engine was lifted slightly with a floor jack and then chained to the 4 X 4. Next the crossmember was lowered for access to drop the pan. We could do this in less than an hour, and it took a little longer to reassemble. Today in our own shop we support the engine with a gantry and a chain fall.

The key thing here is to keep the caster shims on both sides of the front end separate and before reinstallation carefully clean all of the shims, the top of the crossmember, and the bottom of the body to insure that no dirt or debris gets between them. By doing it this way the caster will remain the same after reassembly.

Do not let an alignment shop adjust the caster by shimming the upper control arms. Volvo manuals warn against using this procedure. The 1800's and 122's control arm shaft bolts are only 7/16" dia. and there is very little clearance between the control arm bolts and the shaft and uneven shim packs will bent the bolts. That can lead to bolt breakage in use and difficulty removing them later. It the shim packs are thick, longer grade 5 bolts are necessary, because without full tread engagement in the crossmember the bolts can pull out.

For hard road use, autocross and racing 1/2" control arm shaft bolts are necessary because the small ones can break and pull out the threads in the crossmember.
 

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Do not let an alignment shop adjust the caster by shimming the upper control arms. Volvo manuals warn against using this procedure. The 1800's and 122's control arm shaft bolts are only 7/16" dia. and there is very little clearance between the control arm bolts and the shaft and uneven shim packs will bent the bolts. That can lead to bolt breakage in use and difficulty removing them later. It the shim packs are thick, longer grade 5 bolts are necessary, because without full tread engagement in the crossmember the bolts can pull out.
The shim between the crossmember and the body channel is the primary adjustment for setting caster. It is not explicit; but, reading between the lines in the service manual the presumption appears to be that both the right and left side would have the same thickness shim? The service manual does permit differential shimming of the upper A arm if the right and left wheel casters are different (pages 6-3 and 6-4).

Microsoft Word - part_6_front_end_steering.doc (volvo1800pictures.com)

Alignment shops that have a flat rate for alignment probably hate it when an Amazon or P1800 shows up because shimming the cross member to make a change to caster is going to be a lot of work (if they do it correctly). Might be better off just having them measure the alignment and then make corrections based upon the shim curve on page 6-4.

As an observation, if you think you might try making your own adjustments, alignment shims are less available than they used to be. When I was fiddling with my alignment a year or two ago and needed some different shim thicknesses, the local NAPA, PartsSource and another main line parts vendor had none in stock. I think I ended up ordering from Rock Auto. They came in packs of 25 so I expect I now have enough shims to align all the vintage Volvos that are still moving in my province.
 

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Discussion Starter · #8 ·
I appreciate all the info. It helps understand the Volvo green book part 6 service manual. If I do end up lowering the cross member, I'll take care with the shims under the front bolts on the cross member and find an alignment shop with some 1800 experience to check things out afterward.

Cheers,

Charlie
 
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