Thread: So, 101 drum brakes DO work!!

Originally Posted by garrycol

The idea of the load proportioning valve is good - supposedly auto controls the rear braking effort in all conditions - when loaded increases brakes effectiveness and when stopping where there is weight transfer to the front rear barking effort is reduced stopping the rears locking and possibly loosing control. Unfortunately as set up on the 101 there needed to be a bit more braking in the unloaded state. The piston in the valve only has a very small stroke so it is effectively either on or off with little in between.

When I first worked on my 101 brakes I could not get fluid to the rear brakes because of the proportioning valve being closed. To bleed the brakes I forced the valve open so the fluid could go through it. Later it started leaking so I took it out and pulled it apart to find it was corroded and needed replacement. New from the UK was about $400 at the time so I looked for alternatives. There are manually operated valves you can get from speed shops quite cheaply but I understand these are illegal on a road going vehicle so I didn't go that route - but to me these would be perfect for the 101 as you can adjust them for the load state you are in.

I went to the local toyota dealer and climbed under a Landcruiser and noted their system is basically the same as the 101 except it is activated from the diff in a sideways direction where on the 101 it is fore and aft but the actual valve is about the same size. I went to a wrecker and bought a cruiser valve for about $45 and cut off all its levers etc I had to drill some new mounting holes in the 101 valve mount and did slight mods to the 101 lever so it moved the piston on the valve correctly and adjusted it so that the valve was slighly open on in the unloaded state - the brake pipes were of a different thread but was fixed with an adaptor.

I have never had an issue with 101 brakes except for differential braking caused by the need to constantly adjust them. Never had an issue reversing as the front brakes work equally as well in either direction - also never had the rears lock up and I do know they are working. When offroad whether going forward or back the rear suspension does move a little (noting the rear is 1.5t rated so it does not move much) so effectiveness of the rear brakes varies as the diff moves up and down.

Garry

I'm looking at the load apportioning valve again as mine appears to have given up the ghost and when bleeding seems to let air be drawn into the rear circuit. The things been rebuilt twice in my short ownership, once by the brake shop and another by the local 4wd shop. It moves but leaks quite a bit.

Garry, all the landcruiser valves I've seen online so far have a third connection to the front brakes, I've yet to find a cross section diagram so not sure of the inner workings but did you just block off the front hose connection or does the model you have only have two connections?