MG T-ABC

I want to remove some camber from a TC front axle and seem to remember it can be done relatively easily but should be done "cold", i.e., without heating the axle. However, while reading Clive Sheriff's article (http://www.mg-tabc.org/special-files/ta ... eering.pdf) on steering he states:

" This is rarely in the same shape as it left the factory. It is made of a fairly soft material, and although it
rarely breaks, seems to bend very easily, upsetting all the steering angles. It is fairly easy to reset with a bit
of heat and patience.
First realign the spring plate faces to take out any twist, this can be done quite effectively with straight
edges and oxy-acetalyne. Then with a couple of long 0.075 inch diameter ground steel bars in the king
pin holes, set up the castor and king pin angles to specification against the spring plate faces as the
reference datum."

So....do you bend the axle hot or cold or does it really make a hill of beans?

Also, what happened to Jim Buell's article on setting up the TC steering? It used to be here: http://www.mg-tabc.org/techn-up/Buell-T ... 2nd-ed.pdf but now it's not.

Good question, when I had a rear spring re arched it was done cold, there was a reason and as I recall something about changing the characteristics of the spring steel. Not sure how this would affect a front axle, but I think if I could I would do it cold.

Speaking of missing articles, what happened to my article about a low budget engine stand to run start an XPAG engine on? My feelings aren't hurt, but I am just curious.

Hi Gene, if you have any bookmarks from the old site, they may have changed once the site was re-organized. The Buell front end article is on this page: http://www.mg-tabc.org/resources/tech/

Stephen, where was your article located on the old site? I thought I brought everything over. I apologize for it being temporarily lost in cyberspace.

Thanks Steve...thought I'd looked there but obviously not well enough.

Steve,
It was under the Technical Articles under Engines. I think it was the last article and there were some photos as I recall, thanks

It looks like Walter may have added a few articles since the last "grab" of the site I made, so there are a handful missing on the new site. Thanks for the heads up!

And the answer to the hot/cold question is????

the answer is COLD, no heat. See Service Information Sheet #10.

Bob, thanks. Any chance you can attach a copy of that SB here so I can read it?

When I decambered my racing axle, I had it done by a competent machine shop. It should be done cold and the bend should be outside the mounting plates.

Hi Gene, Mark Jablonsky analysed the steel alloy used for the front axle and found it was a medium carbon, manganese-molybdenum based steel that had been heat treated to a particular hardness. Heat should not be used to help bend the axle as it would destroy the specific heat treatment. Reducing the camber would reduce the understeer characteristic and might not optimise the tyre tread footprint on small roads with a crown.

Eric...thanks...cold it will be then. I'm finally trying to get the car set up for racing so small roads with a crown won't be a problem...other cars and my old age will be.

Speaking of age, I just belatedly remembered that Mike Sherrell's book has a piece, including some helpful diagrams, on the TC front axle. I'd definitely check it out prior to getting down and dirty.

Took the axle to a machinist friend today to try his 25 ton hydraulic press. Didn't move it but it did raise another question.

Right now the axle has about 8 degrees camber at the king pin, with the bottom of the hole further away from the center of the axle than the top of the hole...this seems strange since a TC's front wheel leans in the opposite direction, i.e., the top of the wheel is further from the center of the axle than the bottom of the wheel. Where is this difference in angle made up? And would I need to remove all the camber in the axle or only part of it to bring the wheels to 0 degree of camber?

I're re-read and re-written the above paragraph a couple of time and I'm still confused. Hopefully you can understand what I've written.

Thanks,
Gene

Brown book says:
King Pin angle=7-1/2 degrees.
Knuckle angle=10-1/2 degrees ( the other way ) .
Wheel camber= 3 degrees results.
So your 8 degrees is close for the axle beam king pin angle. The steering knuckles make up the difference to get 3 degrees camber.
A 25 ton press should have moved the axle beam easily, I have used a 12 ton press for the job, guess it depends where you are pressing. If both sides of the axle beam have the same camber, I would press in the center of the beam to alter the camber. Then check the spring pads are more or less flat on a surface table. If not, shim the pad so the spring pads sit flat.
Bob Grunau

Bob, thanks...was hoping you'd reply.

So, you say make one bend in the center of the axle, i.e., raise the center of the axle, and take the camber out that way. We were trying to bend the outer ends (past the spring pad) to remove it. Your way seems much easier but I would imagine you'd definitely need shims to make the spring pads sit flat.

Hopefully I can let you know by next week how it turned out!

Yes I bend the center, but does it not have to go DOWN to reduce camber to zero? Leave slight camber as the whole thing will settle after bending and when on wheels. Make sure both kingpin angles are the same, before you start. Yes shims may be required for the spring pads. Start with the axle on a table saw top or surface plate. I think this is better than trying to bend the outer ends. Use long 10" or 12" long 3/4" diameter rods to reach the flat table top or surface plate you are working on, makes measuring easy between the two kingpins. Also you can eye-ball the relative slopes of the kingpins easily side to side. And soee if the kingpins are the same location front to back. Not rocket science.
Bob

You're right, center needs to go down, not up. Glad you caught that since we were definitely bending the wrong direction. I think I have a spare steering knuckle that we can use to get the angle correct.