Bedford TK problem with air brake

johowell234 · #1 26th October 2016, 16:40

Hello,

I'm in the middle of restoring a 1973 Bedford TK with a 330 diesel engine. It has air assisted hydraulic drum brakes. We've had all the wheels off and cleaned up and checked the brakes cylinders. All is well. The problem is, my park brake (which is entirely air) is no longer working. The mechanism on the back axle seems to be working because when you let air out of the system it does comes on. However, when you pull the lever by the drivers seat nothing happens. We have had the lever apart but nothing seems to be obviously wrong.

Guessing the problem is that what ever is meant to be taking air out of the system is not working? Does anyone have a different solution? Also, does anyone know if the air is dumped out of the system around the back of the lever (there seems to be a port) or does it come out from the servo?

Thanks in advance!

mylesdw · #2 28th October 2016, 04:01

The air comes out from the handbrake lever valve (not the servo) at the back of the cab where the lever bolts on. It's probably the valve, mine did that and I have a new valve to go on but I have not tested it yet. You can get rebuild kits for not too much dough. I think the valves stick when they have not been used for a while and then the air in the system does not blow them open as it should. When mine stuck it felt different when you lowered the lever - like it was not doing anything.

Harvey g · #3 6th March 2019, 18:22

I have same what seems to be the same problem with a tl 1630 park brake won’t work! Had valve to bits can’t find owt wrong but valve won’t exhaust it the back

mylesdw · #4 7th March 2019, 20:09

It pretty much has to be the hand lever; I replaced the the whole thing and the handbrake worked again.

The only other possibility is the change-over valve(s) AKA anti-compounding valves. Two in this picture but you may have only one. There is a piston inside that needs to be able to move freely. I wonder if it is stuck?

Harvey g · #5 7th March 2019, 20:19

Thanks very for info . I have noticed a valve over rear axle which the brake pipes go into I’ll have it apart! The dam hand brake valve has been in bit s twice completely ! Can’t see owt up with it . Any ideas where to get a new hand lever valve??

mylesdw · #6 7th March 2019, 22:07

Picked mine up on eBay, they come up from time to time. I might have a rebuild kit left over if that helps?

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