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MG TD TF 1500 - TF brake woes

I have had a local mechanic (all makes), do some re-fitments for me.
He installed all new brake cylinders (6), and new flex lines (3), and later a new master cylinder.
He has not however been able to give me the hard brake pedal suitable enough to make a road trip. He used the normal procedure of pumping the brakes, then hold while the bleed line is opened, and repeat several times. When I press the pedal it goes about 3/4 down. It will stop the car, and so I removed it to my storage garage, after two weeks in his shop.
Are there any other line bleed methods that I should use to get the desired result?

Lets hear from the experts.

Thanks and cheers, Byron Warwick.
JB Warwick

The brakes on the TF are not self-adjusting. Make sure that the shoes are properly adjusted using the adjustment screws. That should firm up the brakes for you.
Charles Duffy

I have had the same issue.

I believe the issue is that there is no direct bleed in the wheel cylinders. The bleed is in the line leading to the cylinders. getting air out of the wheel cylinders is not easy.

Here is what I am going to TRY, as soon as my PMR gets good enough to crawl under the car.

Relax the brake shoes as far as possible. Pump up the brakes, (Keep the MC full.)
This should move the wheel cylinder pistons as far open as they will go, and get as much fluid into them as possible. Wait 10-15 min for the air to stabilize in the cylinder.
With a foot on the brake peddle crack open a bleed valve. Step on the brake pedal to the bottom. While the brake pedal is still at the bottom, lock the brake adjusters against the shoes. This should move the brake pistons in, to minimum separation and expel any air in them.
You may need to repeat (several?) times.

Disclaimer!
I have not tried this yet. But its may plan.

Jim B.
JA Benjamin

If he turned the drums and then installed new brake shoes the chances are great that the new shoes do not fit the drums.
Pull the drum off and inspect the shoes for full contact.
I have had to hand fit new shoes as tru-arcing is no longer allowed here in USA.
Measure the ID of the drums and as standard they should be 9 inches.If my memorey is working then .030 oversize is max.
Sandy
Sanders

Click on "Archive" at the upper right of the page, enter and search "bleeding brakes". There have been volumes written about this. George
George Butz III

On the front brakes, make sure the adjusters are below the brake cylinders in the front of the drum and above the brake cylinder in the rear if the drum, or you will have trailing shoes instead of leading shoes.

Also, try a bleeding jar instead of holding the pedal down and releasing the pressure with the bleed nipple. Put an end of hose from the nipple to the jar, with the jar partially full of fluid, and watch for bubbles. Especially important for DOT 5 as your method will aerate the fluid. Use slow, even strokes, no pumping.

Warmly,
Dave
Dave Braun

The other possibilty is that the bleed screws are passing air down the screw, this can happen after many year of use. If so you need to fit new bleed screws.
Dave H
Dave Hill

One other thought.
The brake pedal free play is important.
The rod between the pedal and the MC is adjustable.
You noted that you installed a later MC.
It may need adjusting

Jim B
JA Benjamin

I fitted the Ezi-Bleed speed bleeders, made bleeding a snap.

I still use an assistant but keep the master cylinder topped up, and, one slow press of the pedal, not dozens of rapid pumps.

Peter
P G Gilvarry

Put clamps on the three brake hoses, if the pedal firms up the problem is with the cylinders. if you don't have the proper clamps, "G" clamps will do short time.
If it does not firm up then the problem is with the master cylinder push rod adjustment.If that is OK then release the rear clamp and test again, if the pedal goes slack then the rear needs adjusting/bleeding.Repeat with all cylinders.Just make sure you never let the master cylinder run out of fluid and draw more air.
Anybody near you who could help ?
Ray TF 2884

Ray Lee

It has been a while since I started this thread, and for good reason.
Not enough pedal pressure, after bleeding the new wheel and master cylinder.
I had blead them 3 times.
The phrase is in the owner's manual for TD/TF. It was key to getting the job done right. The manual says when bleeding the brakes, "Depress the pedal QUICKLY."
It worked for me and we just completed a 700 mile trip to our daughter's cottage in Northern Ontario.
Cheers, Byron W.
JB Warwick

It is absolutely essential that you lock up the adjusters on each wheel before bleeding. If you don't do this air bubbles in the lines will not be expelled. Don't ask me how I know!

Jan T
J Targosz

This thread was discussed between 02/07/2018 and 30/08/2018

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