Losing my brakes - front/rear adjuster keeps blowing

I have a tweaked Jimny - I got very lucky and bought it from a mechanic who had made it perfect for off-road.  I keep it on our farm and it never goes anywhere else - it's a work horse that copes with very steep hills.

Unfortunately, one of the mods done by the mechanic was bringing a copper brake line up into the cabin in front of the drivers seat with a manual pressure adjuster to balance braking between front and rear.  I've had two blow now, weeping brake fluid and leaving me without anything other than 1st gear and the hand brake. Awkward.

Should I buy a third adjustor (I don't drive above 20mph so can't see the point in the device) or is there a way I can remove the adjustor and fit some form of connector to link the copper pipes up strongly?

Any ideas please?  

Not sure how This is connected but I assume it is Just to reduce the Flow to the rear brakes.
Looks like an air valve though.
The drifting guys got valves for this that can take the pressure.
I would see if I could remove it below instead by replacing the cut brake line.

If it's not a road vehicle I would suggest removing the valve. If it is a road vehicle I would look at reinstating the back axle load sensing valve, assuming it is not an abs vehicle, its more likely to be reliable than a manual valve.

If you just remove it and join the pipes you will find the back wheels will lock when there is no load or you are going downhill. This is A Bad Thing, as the back end will try and overtake the front.

As Lambert says, there should be a load sensing valve above the back axle with a link down to the back axle.

There are two pipes from the master cylinder to the valve, one from the front circuit and one from the rear.
The further down the axle is, the less pressure reaches the brakes.
If the front circuit fails it overrides the valve and lets the rear brakes come on more.


If it is lifted then the link has to be extended. If the valve is there and all 3 pipes connected just join the pipes and it will be standard again


If it has working abs just join the pipes and the abs will stop the backs locking up.

"The drifting guys got valves for this that can take the pressure" - Thanks Yakuza. Replacing the valve with something which works seems the least effort.  Do you have a link to show the correct valves please?

 

wrote:

If you just remove it and join the pipes you will find the back wheels will lock when there is no load or you are going downhill. This is A Bad Thing, as the back end will try and overtake the front.

As Lambert says, there should be a load sensing valve above the back axle with a link down to the back axle.

There are two pipes from the master cylinder to the valve, one from the front circuit and one from the rear.
The further down the axle is, the less pressure reaches the brakes.
If the front circuit fails it overrides the valve and lets the rear brakes come on more.


If it is lifted then the link has to be extended. If the valve is there and all 3 pipes connected just join the pipes and it will be standard again


If it has working abs just join the pipes and the abs will stop the backs locking up.

Thanks for that. Is there an easy way to join those pipes if all the right bits are in place?

wrote:

Thanks for that. Is there an easy way to join those pipes if all the right bits are in place?

 

You want a female brake pipe joiner with the correct thread. 

The correct thread depends on what the previous owner used for the fittings, it should be M10x1, but it could be 3/8" UNF.

As we have no idea what the previous owner did to the braking system, it would probably be safer to just replace with an identical valve.

"As we have no idea what the previous owner did to the braking system...

From the Reg, it's a 2002 Jimny Special.  Here are some pictures - some have some green lines to indicate the copper brake lines.  Does this help?

 

  Also... there is an electric plug and socket. The plug isn't connected - what does it do please? Just so I know whether to replace the plug and socket or just solder them.

Where do the pipes on this joiner go?
I can't tell with those small pictures, but it looks to me like one to the rear axle through that valve inside the car, one to the front circuit, and one to the rear circuit, so the 2 circuits are joined.


 

If you start at the master cylinder.
One pipe goes direct to the NS front wheel (those flexis look a bit short to me, but it might be the photo)
The other two pipes go through flexis to that muddy joiner.
one front outlet goes to the OS front
The other front outlet should go to the load valve above the back axle (that you don''t have)
The single rear outlet goes to the load valve above the back axle.
So two pipes go from that muddy joiner to the rear axle on an unmodified car.

How it should be (non-abs)

 

What I think has happened, I am not sure because I can't see clearly, is that someone has joined both outlets for the rear axle together with 2 arms of a T piece, and run the third arm to the back axle through a variable valve inside the car. This is supported by no front brakes or rear brakes when the seal blows.

 

What I would do FOR OFF ROAD USE ONLY is plug the outlet from the front that used to go to the rear so the front brakes are on their own circuit again, and forget the T piece, simply running the pipe to the rear, either direct, and risk rear lock up all the time, or through a new valve. It won't be a disaster if the valve blows now, as the fronts will still work.

 


That plug on the transfer box I suspect is the speedometer sensor.








 

Awesome response - thank you, that is really helpful. I'll take a video/better pictures tomorrow for clarity.

My Jimny is strictly an off-road workhorse. It has to handle steep slopes and heavy loads/drags, but speed isn't a concern Brakes are though!

 

I made a couple of videos but the forum didn't like them 

If the system is as you think it is, and I think you are right, what are the risks of just bypassing the valve?  Two valves have broken in quick succession so I don't think it's a useful mod, but then I'm not confident I'd make a great job of changing the system myself.   

I was thinking of just epoxy'ing the screw area of the valve to get me going, then replace the whole thing with some adapter at a later stage.  The brakes + mod have been fine for about a year so I'm wondering what's making them fail now.  Any ideas?