New steering rack fitted but column touches chassis

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KFBGT
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New steering rack fitted but column touches chassis

Post by KFBGT » Fri Nov 20, 2020 6:04 pm

Hey, can I ask if anyone else had this?
I stripped off all the front suspension from my 73 BGT and replaced everything apart from the crossmember.

It had the camber wedge kit already fitted, which I put back with new poly Bush pads between the crossmember and chassis.

After installing everything including a new Moss rack, I've just noticed that the lower part of the steering column coming from the rack is touching the chassis leg in the engine bay. Not jammed hard against it as the wheel turns OK, but I'm sure it didn't before.

Anything obvious spring to mind before I start the process of undoing everything?

Ian Fozzard
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Re: New steering rack fitted but column touches chassis

Post by Ian Fozzard » Fri Nov 20, 2020 9:56 pm

Very difficult to say anything about this without more precise information. It sounds like you have a whole raft of non-standard parts fitted, so I would guess that's where the problem lies.

I can post a photo of the rack position on my '72 BGT tomorrow if that might help?

Otherwise I think you need to reassess all of those mods you have on your B

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

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Charles Farran
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Re: New steering rack fitted but column touches chassis

Post by Charles Farran » Sat Nov 21, 2020 11:21 am

There is a current discussion going on the MGB tech section of the BBS site about steering racks including when they changed & length of the pinion before meeting the UJ of the steering column. If you have the wrong one then clearance is an issue.
Discussion covers 1972 / 3 cars etc.
Cheers
Charles
1980 Roadster

Ian Fozzard
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Re: New steering rack fitted but column touches chassis

Post by Ian Fozzard » Sat Nov 21, 2020 11:28 am

I've just had a look at my 72 BGT. The column passes the side chassis with a clearance of circa 2-3 mm.
There is a stage of mounting the rack which involves shims under the rack mounts. This is to ensure that everything aligns with no sideways forces. You must follow this and insert the shims as required. If you do this you may find you have adequate clearance.

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

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Paul Scott
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Re: New steering rack fitted but column touches chassis

Post by Paul Scott » Sat Nov 21, 2020 11:40 am

From the original service manual 14th edition.
Screenshot_20201121-113347_Acrobat for Samsung.jpg
If you havent already got this manual KFBGT and you would like a copy drop me an email.

StaySafe

Paul
webmaster@mgb-register.org
1975 MGB Roadster
Webguru for MGB Register

Ian Fozzard
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Re: New steering rack fitted but column touches chassis

Post by Ian Fozzard » Sat Nov 21, 2020 12:18 pm

One thing you need to be aware of: there are different methods for alignment in the various manual editions.
One of these involves the use of pointers attached to the meeting ends of rack and column. I have never used this method - seemed designed for later Bs - and it seems quite impractical.

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear

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Peter Cresswell
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Re: New steering rack fitted but column touches chassis

Post by Peter Cresswell » Mon Nov 23, 2020 9:38 pm

This may help you:
viewtopic.php?f=3&t=39&p=211&hilit=steering+rack#p211
The instructions that come with the Castor Reduction wedges don't tell you about the need to re-shim the rack to get the correct alignment. This is made clear in the thread above, so check you have extra shims fitted to the rack mounts. Speaking from memory I think the extra shims go under the lower bolts on both sides of the rack, but I can check on my car tomorrow and post a picture. I suppose if you need to move the rack mast left or right as well you can shim one side more than the other but I have not had to do that.
Pete
1969 MGB Roadster
2020 MG HS Exclusive
2007 Mercedes SLK
Plus 34 other cars since 1965

KFBGT
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Re: New steering rack fitted but column touches chassis

Post by KFBGT » Tue Nov 24, 2020 6:41 pm

Thanks Pete,

If you can post a couple of pics of your install that would be helpful.

I watched John Twist from university motors video about aligning the column uj with the rack. I added shims, washers but not convinced I got it right. The pointy alignment tools recommended look tricky, so I went with his advice.

I have poly bushes on the crossmember mounting to the body, the camber wedges are fitted in the same position as when I stripped it out and the standard Gaz shock conversion, which doesn't seem to have any affect on the geometry.

I'll check the alignment again to see if they are even on both sides of the rack mounts.

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Peter Cresswell
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Re: New steering rack fitted but column touches chassis

Post by Peter Cresswell » Wed Nov 25, 2020 9:28 am

Hi Karl
I took some pictures yesterday but they don't show clearly where the shims go or the closeness to the chassis of the rack mast. I'll try again tomorrow.
When using the castor reducing kits, you have to tilt the front of the crossmember down to reduce the castor angle of the king pins. This will tip the rack mast upwards and at the tip it will be quite a bit. To correct this, the front mounting of the steering rack has to be shimmed to to bring the mast down again so it lines up with the steering column. Using the pointy alignment gauges makes this an accurate alignment, but it is fiddly and the rack mounting bolts have to be tightened the mis alignment judged, then the bolts loosened and with the front ones removed shims can be added, and the bolts then tightened again, and the gap reassessed. Then repeat and repeat until it lines up. So it is a fiddly job rather than complicated. I've watched the John Twist video and it is fine if you have a mate handy to turn the steering wheel whilst you add the shims. It is still a bit trial and error though.

I didn't use the wedge type castor reduction, as I am not convinced by the engineering, but I used the Brown and Gammons kit which uses square steel mounting plates that go between the rubber (or poly) pad and the underside of the chassis. These plates are the packing to tilt the crossmember and they are securely held in place by the from crossmember bolts. This kit is also also came with new poly crossmember mounting pads and 6 rack packing shims of which I had to use 4, and it also has the advantage of being about 2/3 of the price of the wedges!

With the wedge system they have to be inserted from the front of the crossmember so that the fat end is to the front. Is this how you refitted the crossmember to the car?
Pete
Pete
1969 MGB Roadster
2020 MG HS Exclusive
2007 Mercedes SLK
Plus 34 other cars since 1965

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Peter Cresswell
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Re: New steering rack fitted but column touches chassis

Post by Peter Cresswell » Wed Nov 25, 2020 8:54 pm

Hi Karl,
I can't get a decent picture showing the shims for the rack mounting, but I have managed to picture the clearance between the steering column and the side of the chassis rail,
Steering Column Clearance.jpg
The clearance I have is 0.5cm as shown on the picture.
As you have recently removed the crossmember from the car, I suggest you check the crossmember is fitted correctly (unlikely as the bolts have tapers on them). That the rack mountings are not bent or broken. That the rack mounting bolts have the same thickness of shims under the front bolts on both sides. If all this checks out ok, then it might be worth an email to Moss Technical to see if they have any ideas about the problem and check you have the correct rack for your car as they list 2 racks in their catalogue - GSR136 for cars up to 1974 and GSR135 for cars 1974 on. They are both the same price so you can't check using the price!
Moss contact:- https://www.moss-europe.co.uk/contacts
In subject box, click on the arrow on the right to open a drop down menu and select 'Technical question'. I have found them very helpful!

Pete
Pete
1969 MGB Roadster
2020 MG HS Exclusive
2007 Mercedes SLK
Plus 34 other cars since 1965

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