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MG MGB Technical - Steering Rack and Flywheel Bolts

My rack was leaking oil so I decided to replace the shaft seal and renew the other seals. Before disassembly the rack was very smooth to rotate but now that I reassembled it the gears feel notchy while rotating. I read the Bentley manual and did as they said but after shimming the rack the notchiness continued. I noticed that the damper was grooved and there was some wear. When I removed the shaft did I upset the mating of the gears? I tried this on another rack I have with the same results.

What is a rack supposed to feel like?

FWIW, the original rack was worked on as evidenced by teeth marks on the damper and the lack of a spring in one of the tie rods.

Next question. Is there any reason I cannot use 'regular' bolts to attach the flywheel to the crank which have a deeper head? I plan to red loctite everything down so I have no need for the retaining ring. There doesn't appear to be a interference problem and those shallow head bolts made it difficult to get them off w/o rounding off their corners.
Mike MaGee

Mike

A tip for the flywheel bolts (based on experience after having to drill one out). Make sure you use a six point socket - the twelve point are ineffective. Socket grip can be improved by grinding down to remove the lead in radius. I assumed that the shallow head bolts were used to ensure clearance to the clutch plate.

Barry
73B
B.J. Quartermaine

Also I would avoid red locktite as it can damage the threads when you remove them later. Stay with Blue! Bob Thompson
RHT Thompson

Mike - speaking from actual midget experience only (tho' I expect the B to be similar), the pinion shaft has to be aligned a certain way as it contacts the "middle" of the rack gears. You can tell where the middle is by the case hardening that's done to three or four teeth on the rack, as they get the majority of the wear. These teeth have a characteristic color from the heat treatment.

Best of luck - - Alec

.
Alec Darnall

The rack might feel a bit notchy while it's in the air, but should be smooth on the ground. If it's notchy on the ground it's probably too tight.

Do you really have so much wear that the factory shimming isn't enough anymore? It's not all that likely unless you've gone a very long way (or a somewhat shorter way with a dry rack). Something else may be at fault. I think I took out the very thinnest shim on mine.

Couple of the problems I ran into:

Make sure the shims are properly aligned - that the damper is riding on the cover and not on a shim - this can happen on reassembly after all of your careful measurements.

The damper pad (item 10 in the picture at http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29018, the moss catalog for steering) tends to wear - you'll see a bright line/groove on it. If you turn it 90 degrees and re-install it's good for another 200k miles often without adjusting the factory shims. If it happens to shift around while you're installing shims, measuring, or final assembling it can throw your shim counts off.
Mike Polan

The last rack I did was notchy after adjusting it as described in the shop manual. Adding one thin shim solved the problem.

Clifton
Clifton Gordon

Hi Mike:

The shallow heads on the flywheel bolts is to allow for clearence to the clutch disk hub. A lesson learned regarding critical bolt design and application! leave it like the way the designer designed it, use OEM bolt and correct locking tab. Never trust Locktite in critical applications, a general rule is to use tab washers, castellated nuts/split pins, etc. Regarding using alternate hardware in critical applications requires analysis of heat treatment issues, and impact of the fatigue environment.

Good luck:

Rich Boris 67 B
Rich Boris

Mike
I go one stage further than Rich Boris - always use new securing bolts for the flywheel and follow the makers instructions to the letter - consequences of them sheering are catastrophic.
Roger
RMW

This thread was discussed between 26/07/2005 and 28/07/2005

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