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MG TD TF 1500 - Master Cylinder push rod

My TF brakes have been dragging even tho I took .050 off the piston...using I took the master cylinder off to see what was up and it looks like the after market push rod and clevis combination is too long so that there was no clearance as required. Have any of you run into this problem? I did a quick search of the archives without finding anything.
Terry in Oakland, CA
Terry Sanders

terry, if it is the same as the TD my master cylinder push rod has an adjustment for length. regards,tom
tm peterson

Dragging, as in staying on? Does the brake light stay on?
gblawson - TD#27667

Tom, yes they are the same but on these after market part with the adjustment completely taken up I was still pushing on the piston. I cut 1/4" off the clevis threaded part and now I have some adjustment. Just did a test run and that was surely it but I have put a little too much slack in the pedal so tomorrow, will readjust.

gblawson, yes the brakes were on and the hotter they got the "on ner" they got! Pedal right to the top.
The brake light would go off and then come back on.
I put a pressure gauge in the line instead of the stop light switch and go an incredible 40 psi at times....this is when I learned that there should be about 8psi in the lines with brakes off. I had missed that tidbit after all these years.

Terry in Oakland
Terry Sanders

If you look straight down into the mc resevoir there will be two little holes...about a quarter of an inch in dia... the front one has a 'really' tiny hole in the middle of it...about the size of a pin. It is the relief valve. Take a needle (or better yet, a tool for cleaning out torch tips) and run it through the hole.
Mine was plugged and wouldn't release the pressure... just kept increasing the brakes.
There is a drawing in the TD shop manual if in doubt!
gblawson - TD#27667

Could it also be the silicone-swelling-the-rubbers-so-covering-the-bypass-hole problem?

Did a quick search in the archives and found at least two threads on this problem:

David Wardell

I switched to silicone and found that the original rubber washer (the furthest one in the mc) had been missed and left in...the new one was on top of it. The silicone had attacked this one and caused little 'black floaties' to clog up the hole...(hard like iron)... Took the mc apart three times before I figured the little hole was plugged...exact same symptoms. Started with the brake light staying on and ended with the brakes locked on while driving....mmmm the smell was incredible!
gblawson - TD#27667

I'm well aware of the bleed hole and it is clear, checked again yesterday. I'm also well aware of the problems that silicone fluid caused in the past with old rubbers or rubbers that had previously been immersed in glycol based fluids. That is why I took .050 off the the length of the piston. Thanks to those who have replied.
Terry in Oakland
Terry Sanders

Other then the rubber hoses to each wheel acting like one way valves, not sure what it might be then?
gblawson - TD#27667

It is clearly the after market pushrod/clevis pin being too long...problem now solved. By surfing around, I see that gblawson's name is Gordon. Glad to meet you Gordon but why don't you sign your emails?
Terry in Oakland who doesn't hang on this list that often.
Terry Sanders

Sorry Terry...never thought about it....


gblawson - TD#27667

This thread was discussed between 19/06/2007 and 20/06/2007

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.