MG T-ABC

The hand brake on my TC has stopped locking when applied, What should I be looking at to repair?
Thanks.
Jim Yergin

First make sure the wing nut adjuster on the lever didn't unscrew itself, then check the adjusters on each cable under the car. Also make sure the cables haven't jammed. Look for a bunch of slack where they come out of the outer housings and connect to the lever cross member. If both went out at once, it's usually an issue at the lever, or perhaps the rotating shaft has jammed.

According to the picture in Moss, it looks like my TA brake handle. I understand you to mean the fly-off feature is not working.
There is a sliding pawl, held by two hex head bolts, that moves down when you push the knob, and hooks into the gear on the frame. If it is failing to hook, but still the knob pops up again, then I suspect your pawl is out of position or gunked up with rust or the bolts are too tight or the wrong bolts.

You're right, Rob! I read it as the brake not engaging. So the question is... does the button move when you depress it? In my experience the most common reason for the lock not holding is that the brake is set too loose. Try tightening the wing nut in front of the handle (under the vinyl boot). The pawls do wear out also but they're pretty durable. Also if there isn't enough spring tension on the cables, the lock won't hold. It requires some pulling force to keep it engaged with the teeth. You can simulate this by pressing the button down, push the handle forward and then release the button which keeping forward pressure on the handle. If it doesn't slip then the teeth are probably ok. If not, they are likely bad.

The pawl, part #24 in pic has been known to crack/break, and symptoms can be similar to those described. pic from abingdon spares
https://abingdonspares.com/collections/brakes-tc

Here's the hand brake assembly from TC 7018 (after much scrubbing and painting). The part Duncan mentioned is the black piece with two bolts in it on the left. Or in Rob's photo on the right.

Thank you all for your suggestions. They give me direction as to what to check. The button on the handle pushes down but it will not hold and it pops right up.
Jim Yergin

Good news, When I went to followup on on the suggestions I first tried the hand brake and it worked, repeatedly. That is the kind of "repair" I really like.
Jim Yergin

I love it when they fix themselves.

Could have been some sticky grease in the cables, etc that prevented the springs from pulling back on the lever.

Jim Yergin wrote: ↑

Tue Aug 22, 2023 8:01 am

Good news, When I went to followup on on the suggestions I first tried the hand brake and it worked, repeatedly. That is the kind of "repair" I really like.
Jim Yergin

Jim, I had similar happen on TC2190. Turned out the bolts were loose on the pawl (item 24 on Duncan’s parts list) and that meant that sometimes it worked fine and sometimes not.

Rob's photo shows some badly worn teeth! By using the adjustments, the lever can be brought onto a less worn part of the quadrant .which will give more positive locking. Often the pawl gets damaged as well: I have these in stock, and am about to do more quadrants.

Roger
AKA "Mad Metrics"