Very light sensitive steering

[142 Guy]

Originally Posted by ciderman

I have been told to loosen it by local volvo man but his vehicle feel sloppy BUT, run ok at speed..

Backing off the set screw which establishes the free play on the pitman arm shaft will increase the play / dead zone felt at the steering wheel. I would tend to avoid that advice. The service manual sets out the correct procedure for adjusting the set screw.

The amount of positive caster you are running should be giving you heavy steering. Doing camber measurements at home with a jig is not too hard if you have an absolutely level concrete surface or correct the measurements for the amount that the floor surface is out from level. Caster measurements are harder and you really need a set of turn plates for accurate measurement. The 20 deg tape marks on the floor is an OK approximation if you have big changes in camber. Not so good for small changes in camber where small differences become important. When you did the caster measurements at home did you do the + and - 20 deg camber angle measurements (or whatever Volvo recommends for this particular model)? If so, is there a chance that you messed up when it comes to adding or subtracting the two angles? The instructions associated with some of the home alignment jigs are really confusing, particularly the details around when you get one positive and one negative camber measurement at the two 20 deg angles and how you add or subtract the two values.

I would be inclined to pay a visit to a good alignment shop and ask them to do the measurements. You may need to search a bit to find an alignment shop that can do vintage vehicles. Most of the alignment shops are using automated systems and they don't really know how do do the measurements. If your car is not in the data base they are lost.

[Derek UK]

As 142 says it would be good if you can get a set of numbers for your front end alignment so that you can understand how it is working. Th rear end cannot be adjusted, but a modern system may use fittings on the rear end. They may show a degree or so out of line but there is nothing you can do about that. It is however vital that all of your bushings, front and back, as well as your ball joints, including the idler arm bush, are good with no obvious wear. Inspect those critically and replace as needed before spending money on an alignment or even a base measurement session. Caster and camber can only be adjusted with Volvo shims. If the cross member is original to the car and hasn't been removed or changed the caster should be OK. Camber can be moved from the factory setting to a very small amount of negative by adding extra shims. Adding one thick extra one of the type used as installed not a bad start. Don't try to adjust the caster by using these thick shims in just one position as this will strain the bolts and potentially cause them to break. If you are replacing the commonly worn upper inner cotton reel bushes it's a good time to add the camber shims. Most of the usual suspects should be able to supply these if you can't get them from a spares car.

[142 Guy]

It occurred to me that the Amazon has that 'interesting' arrangement where caster is adjusted by two means:
- inserting shims between the body and the cross member at the rear attachment bolt
- inserting shims at the upper wishbone attachment point

Rustinmotion had previously alluded to this. Shims between the body and the crossmember are to be equal so that the crossmember is not distorted, so presumably this makes an equal change in caster on both the left and right. If you have differences between left and right caster values you use the shim differences on the upper wishbone attachments to correct for differences between left and right. The service manual is not explicit on the priority of these adjustments for setting alignment. Reading between the lines, I would expect that with equal left and right (or no) shims between the crossmember and the body, you would then adjust the upper wishbone shims to get equal (but probably incorrect) caster on the left and right. You would then add equal (left and right) shims between the body and crossmember to get the caster value to its final value. You then get to correct the camber value because caster adjustment is always done first and if you have used the wishbone shims to adjust caster you have automatically screwed up camber. If the mounting bolt at the upper wishbone is seized up, it will either be very difficult or impossible to correct the left to right caster problem and impossible to correct camber on that side because camber changes require equal shims under both attachment bolts. The left to right caster problem should not be causing your 'floaty' issue; but, getting them balanced should make it easier to figure out what is going on with your steering.

I expect that most alignment shops will not be familiar with the two caster adjustment process for the Amazon so if you get alignment set by a shop you will probably have to have a discussion with them about the process. They probably will not want to do this for a flat fee because the business of having to jack the car up to insert the shims between the crossmember and the body , drop the car and check and then repeat if necessary is something that modern alignment jigs (that I have seen) are just not set up to accommodate.

I am still left wondering whether the signs on your caster calculations have not been flipped. Negative caster does make for light steering and if your + 3.0 / 4.5 deg were actually - 3.0 / 4.5 deg this would turn your car into a squirrel chaser at higher speeds. Grocery shopping carts run with negative caster which makes for easy maneuvering around the aisles; but, notoriously unstable at speed.

[amazon69]

Having just done all the alignment on my car after rebuilding it, and having read all of this thread, I think this:
"I am still left wondering whether the signs on your caster calculations have not been flipped" Is the most likely culprit. Because it is very easy to do.

This link may be helpful to you, it was to me.

[norustplease]

Silly question, but you have checked your tyre pressures?

[Bracpan]

Originally Posted by norustplease

Silly question, but you have checked your tyre pressures?

I agree why are you running only 24lbs in the front tyres ?