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MG TD TF 1500 - Brake drum specifications

Could not find this info in the archives or in the manual.
What is the measured specification for max wear on a wire wheel brake drum?

Thanks.
Tom
'54 TF
T Norby

I've never seen one published.
MG LaVerne

Would it be the same as the MGA1500 W/W brake drum? Not familiar with TF cars.
...CR
C.R. Tyrell

A few months ago, Tom Maine gave us some measurements.
I hope he will chime in.
I failed to keep his info back then.

Tom
T Norby

Apparently its in Blower, I had a quick look at my copy but no sign - will check some more, also stamped inside the drum itself?
mog

The standard drum is 9". Based on my experience, there is a lot of meat on a T-series drum (not TC), so my opinion is that you will run out of brake adjustment long before you have an unsafe drum. I've never seen an "unsafe" figure given, only a figure at which you will run out of adjustment. When these cars were in production it was easy to get new drums; not so today.

I NEVER have drums turned; new drums are rare today (other than Alfin's), and original drums very seldom show the kind of uneven wear that requires turning. I sand them smooth and clean with sandpaper and a Scotchbrite pad, and clean them well.

To increase the adjustment amount I use either a penny on the top of the wheel cylinder, or weld a shim onto the adjuster.

My guess is that with a drum at .050 oversize you will need to shim the adjusters, but the drum is still plenty safe - unlike an American or thin drum.

Look in the archives for shimming information.

Tom Lange
MGT Repair

t lange

Thank you Tom Lange!! This is the information I wanted.
My brakes have been set up with shimmed adjusters for 6 years and several thousand miles. I can presume that my drums are at least .05 oversize. I think they are the originals.
My braking system is in good order. All the wheel cylinders have been replaced, as has the MC. The linings are good. They arc with the drums. Nonetheless, the braking power of my car seems poor to me. I had been thinking of new drums, on the front at least.
My car has wires. Little British is selling the correct drum for less than $55 each. So, they are not rare or costly.
What can I expect to get in the way of improved braking, from new drums?
Is that a question anyone can answer?

Tom
'54 TF
T Norby

Check thew front forward cylinders on both sides - are they pointing up or down? They should be down.

Also, be sure the brake hoses are pretty new - they tend to collapse internally, and leave a small orifice for brake fluid, and create all sorts of problems. Be VERY sure you have no air in the lines, as that can cause reduced efficiency.

I doubt your problem lies in the drums; I would look elsewhere. There's really nothing that CAN go wrong with the drums.

Tom Lange
MGT Repair
t lange

Can someone identify the original manufacturer of the brake drums? Once this information is to hand the issue is to determine if they still exist and then make contact with them to obtain the original manufacturing specifications for the drums.

Other attack might be to contact a reputable automotive brake refurbish er to obtain their opinion. A different
perspective may be the ability of a machined drum to retain or disperse heat and the possibility of the drum warping.
G Evans

Tom,
I also don't think the problem is with the drums,,,,,Tom L has good sugestions to check,, I had poor braking a while back, and it turned out that the shoe linings that I had put on locally were too hard! At the time, it seemed like a good idea to have them done locally,, but since then Moss has reduced their prices for shoes, AND they are using newly manufactured shoes, ie not relining old warn shoes,, The new Moss shoes made a HUGE difference in stopping power!!! Try those before getting those new drums,,,

Maybe your linings are glazed ????

SPW
Steve Wincze

Thanks for the tips. Yes, my cylinders are oriented properly. I looked through my receipts, and the front hoses are not as new as I thought. Probably 15 yrs old. I'm going to replace them, as a first step. Rear hose was new in 2010.

My shoes were new about 3 years ago. I have thought, like Steve, that they were "too hard". The brand is PowerTune. Anyone have experience with this brand of shoes and linings giving problems?

Tom
'54 TF
T Norby

This thread was discussed between 01/02/2015 and 02/02/2015

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