Steering not self centering after rebuild

[KSM62]

Hi all

I bought my Stag in Jan 16 and so far havent had a great deal of use out of it. In the time I've had it I've had to do a number of time consuming jobs including replacing the brake lines, front floor pans, head gasket and water pump. All this started when the PAS rack blew I decided to stip and polybush the front suspension. The first attempt at getting it MOT'd failed when it was discovered that the replacement PAS rack was leaking. I sent this one back for another replacement and at the end of last year it finally got a fresh MOT and I was able to get the tracking sorted and get some short test runs out in it before laying up for the winter again. However one major problem was that the steering was now quite heavy and would not self centre. The worry was that I had somehow messed up the geometry of the suspension. Last week I took the car out for its first run of 2018 before the bad weather came in and there realy is very little self centering effect. Its actually quite unpleasant to drive now. When I got back I raised the front of the car off the ground and found little difference in the weight of the steering leading me to wonder if the problem is less likely to be with any of the polybushes and more likely to be a problem with the steering column or the rack.

The rack, which was £140 from ebay M&P power steering, is now out of warranty, so I want to make absolutely sure the problem doesnt lie else where before sourcing yet another rack. Any advice on the best sequence of testing this problem is greatly appreciated.

Keith

[Kithmo]

It could be stiff ball joints or track rod ends. The steering geometry castor affects the self centering, but this wouldn't usually make the steering stiff.

[milothedog]

Disconnect the rack from the column at the short shaft and split the track rod ends then you can check Column, short shaft and each side of the car, etc for tightness. Does the car drive in a straight line ok or do you need to keep correcting the steering? If you do suspect its the rack that is tight you could try readjusting the thrust pad and greasing it at the same time. the Rom tells you how to do this, it quite easy.

[Phil S]

Hi Keith
sounds like the rack to me.
drop the track rod ends off and you can then try turning each upright to check the resistance is equal and not to heavy.
you can also then run the rack from side to side with no loading on it.
my steering is poor to self centre and needs a very little help.

Phil

[Ian928]

I had the same thing with my rebuilt steering rack. The rack was very tight in the beginning, to the degree that the release valve on the PAS opened partially in normal use. It was very unpleasant with no self centering. I disassembled the front suspension to check my rebuil top joints only to discover they turned very easy. I was advised on this forum to just drive the car and the rack should ease up and it has become pleasant to drve again!

[KSM62]

Thanks
The car drives straight without wandering but you have to turn the wheel to bring the wheels to straight ahead. I've now found the section in the Autobooks manual (nothing in Haynes) and think I understand the process, but I dont have a dial guage to measure any movement and would imagine that its not particularly easy to get an acurate reading with the rack on the car. How do you effect movment in the rack front to back. Do I just grab hold of one end of the rack and pull/push? Is it acceptable to do this by trial and error by slacking off a fraction of a turn at a time and taking it for a test drive? Do I use multipurpose LM grease or something else? My guess is that the rack refurbishers have just tightened the pad up too much which does make me wonder how well the rack has been refurbished.

Keith

[milothedog]

Thanks
The car drives straight without wandering but you have to turn the wheel to bring the wheels to straight ahead. I've now found the section in the Autobooks manual (nothing in Haynes) and think I understand the process, but I dont have a dial guage to measure any movement and would imagine that its not particularly easy to get an acurate reading with the rack on the car. How do you effect movment in the rack front to back. Do I just grab hold of one end of the rack and pull/push? Is it acceptable to do this by trial and error by slacking off a fraction of a turn at a time and taking it for a test drive? Do I use multipurpose LM grease or something else? My guess is that the rack refurbishers have just tightened the pad up too much which does make me wonder how well the rack has been refurbished.

Keith

Yes trial and error will work. LM grease. I also suspect it may be a case of over eager adjustment.

Just one thing to note, when adjusting the pad make sure you check both locks for tight spots, most parts are reused and because the rack spends most of its life in the straight ahead position that's where the wear takes place. So adjustment set to an acceptable tolerance straight ahead may be too tight on the rest of the rack teeth when off centre.

Ian.

[KSM62]

Thanks, I'll try that next weekend and report back.

[jakesmig]

I had a similar problem and traced it to an extremely stiff UV joint on the lower shaft. downside is you need to take the shaft off to check if it is the problem or not. Definition of extremely stiff in this case means clamping the end of the shaft in a vice and stirring the other end was still a lot of effort.

[KSM62]

So Sunday and first opportunity to adjust thrust pad. Back off 1/8th turn and go for a quick test run. Did this until 1/2 turn with no noticable difference. Wound back a full turn still nothing so I removed the plug to investigate and couldnt see any grease. refitted the plug, pumped in some grease. I dont have a grease nipple so pumping through the open hole may not have been that effective. Reset and repeated adjustments. This time a very slight improvement but not good enough. Raining now so will have to come back to this next weekend.