OK, who has done this conversion?

I was told it was easy - yeah, right!

Three days and $200 and I'm back where I started.

Got it all together, finally, after three trips to clutch and brake specialist.

Mounted the new master cylinder for handbrake under the passenger seat in the Moke. re-positioned the rear brake pressure limiting valve in the front side-box, and replaced where it was in the rear with a T-piece.

Pipe from t-piece at front, near master cylinder, goes to the limiting valve in the side box. One side of the limiting valve is blocked off. The other has a pipe that goes to the new handbrake master cylinder. Line from the outlet of new master cylinder goes to the rear brakes.

I have an adjustable push-rod on the handbrake master cylinder, and a couple of cables to stop the piston being pushed out too far when the pedal is pressed.

Nice long handle for the handbrake pointing straight up, pivoting at the floor and pushing the push-rod straight into the cylinder. All worked well.

However - if I adjust it so I get a good pedal for the brakes, the handbrake doesn't return all the way and acts like a one-way valve, building up pressure and locking on the rear brakes.

If I adjust it so the hand brake releases properly and works correctly, then I have no pedal, and even when pumped up is really spongy.

After much trial and error, and bleeding the whole system from every joint to make sure there was no air, I was able to get a compromise between a reasonable, but spongy, pedal, and a terrific handbrake.

But, the handbrake still wasn't completely releasing and the back brakes did get a bit hot after only 5 minutes driving.

Now, importantly, I have drum brakes all round.

So, what have I done wrong? How can I get both a good pedal and good handbrake, without locking on the back brakes?

I finally gave up trying to get it ready for Hay this weekend, and have disconnected the rear part of the system completely. I now have normal brakes on the front only - which work really well and have a brilliant pedal - and a normal cable handbrake.

I have left the hydraulic handbrake master cylinder in place and all the plumbing, just blocked off before the limiting valve.

When removing the handbrake handle, etc, I did find a bit of brake fluid inside the car. Feeling around, it appears to be coming from where the pipes go into the new master cylinder. Could all the problems I have had simply be from the master cylinder not being 100% sealed?

If you are going to Hay and think you can solve the puzzle, please come and have a look.

Any suggestions welcome (as long as they are not rude or silly).

Cheers,
Watto.

pictures might be a good idea.....

this is the way the system should work - the hydraulic handbrake's master cylinder is inline with the main pipe that goes to the rear brakes... which sounds like the way you've set it up.



it's normal to lose a little bit of pedal, but obviously not as much as you're describing

sounds like the handbrake MC is doing something it shouldn't, what sort of MC is it?

here's mine - Series 2 Land Rover, does it look like this?

Yes, I know pics would have been a good idea, but I didn't take any. Just spent time ranting and cursing and getting frustrated.

OK, yes it is plumbed exactly as in your diagramme, and it appears to be the same master cylinder - a generic PBR part (4827 I think from memory).

Cheers,
Watto.

How much travel have you got in the actual hand brake. you may be sitting the piston seal on the inlet which would let fluid past slowly but not let it back?

_________________
1962 850,Frog

This was an early problem. The piston on the handbrake was not returning all the way and was blocking the outlet, so the brakes were locking up and not releasing. As soon as I back off the adjustment to get full movement in the handbrake, and therefore release the rear brakes, I lose brake pedal.

Pumping the pedal up gives a pedal, but very spongy, but as soon as it is released, there is no longer any pedal.

By very fine adjustment - one flat at a time on the adjuster nut - I was able to get about half pedal, but spongy, and good handbrake, but the rear brakes were still on slightly, so I have to suspect that the handbrake was not returning completely and still stopping some of the fluid from returning to the master cylinder.

The adjustment is very fine - a little one way and no pedal; a little the other way and the brakes won't release.

With the rear section, including the new handbrake master cylinder, disconnected and blocked off, I have perfect pedal, so there is clearly no air in the front section.

Could these problems be caused by a tiny bit of air trapped somewhere in the rest of the system?

If this is the case, and I have bled and bled the system and cannot get any more air out, how do I ensure the rest of the air is removed?

Cheers,
Watto.

Watto,

I know it is now way too late . . .but in the days of rallying with rear drum brakes we pushed the knob of the handbrake in, drilled a hole through the lever and the push button and put a split pin through both. This disengages the ratchet so the lever becomes a fly off type - but it could be changed back at the end of the rally to a normal handbrake.

Cheers

_________________
Dave K.
1979 Moke Californian + 1981 'Coke' Moke

Hi Dave.

I already have that modification, but was after something with more pull and less effort - particularly as Mr 12-year-old is competing in his first Hay and wants to have a go at handbrake turns.

I have a couple of ideas where some air might be getting into the system, but I can't do anything about them until after Hay.

Thanks all the same.

Cheers,
Watto.

Watto,

The way you are describing it is exactly how the Coakleys did it to their Moke. I've planned the same modification and put the valve in the side box and a T piece in the rear subframe when I built my Moke for exactly that purpose. But I've not got around to fitting the handbrake yet.

A few thoughts:

- Which proportining valve did you use? The early cylindrical type relies solely on spring pressure, the later square type uses a ball bearing rolling up a ramp. With this latter type the angle of the valve can cause wierd problems with the rear brakes. The arrow must point to the front of the car and you have to alter the angle of the valve up or down to adjust the pressure cutoff and prevent the rear brakes locking or dragging.

- Did you bleed at the proportioning valve to ensure there is no air in there?

- If you bypass the handbrake cylinder completely (use the joiner you probably removed from the side box) and bleed again, does the pedal problem go away? You might simply have a duff proportioning valve that didn't like being disturbed. I have a brand new, never used square type you can borrow and try if you want. I can drive down and meet you at Lara tonight or something if you need it.

Cheers,

_________________
Brett Nicholson
Greendale (near Ballan) VIC.
1971 Morris Mini Moke
1966 Austin Mini
1965 Morris Mini Traveller
1973 LR Series 3 88
2007 LR Freelander 2

Hi Brett.

Thanks for the offer of driving down, but no need. I have shelved the handbrake plans until after Hay.

I am using the early-type limiting valve for the very reasons you describe. A number of people told me this type does not matter how you mount it, as long as the fluid travels in the correct direction through it.

I have spoken to Jeremy (Coakley) and he is a bit miffed about my results - or lack of.

Mike Holloway said he had exactly the same problem when he fitted a hydraulic handbrake, with drums, and the only way he overcame it was by fitting discs.

As I said, I've got another couple of ideas, which I will be looking into after Hay.

Cheers,
Watto.

call that one a co-incidence.... plenty of successful hydraulic handbrakes with drums all round