Brake problem

[Csaba]

I have an intermittent problem of lack of braking power + hard pedal. It is maybe once every 10 braking.
I did all the tests recommended to check brake booster & vacuum, but could not identify the problem. Pressure seems to hold well.

One thing is odd though. When I start the engine after having emptied the vacuum reserve and pushing the pedal strongly, there should be a little down movement of the brake pedal when I start the engine to show that the booster is functioning properly. I my case, however, there's quite significant movement, maybe 2 inches down.

Is it possible that the problem is caused by the load sensing proportioning valve which does not put proper braking power on the rear wheels? My LSPV cannot function properly as it is tied to the carosserie, 30cm above the rear axle, but I am in Cameroon and it is difficult to find someone to fix it...

 

[jblueridge]

When I had brake bleeding troubles a year ago someone here on MUD suggested that I clamp the rear brake hose blocking the flow of fluid to the rear. I was able to get a better idea of the problem's location.

Another tale of difficulties...
BJ73 sinking brake pedal issue with solution

 

[roscoFJ73]

Is it possible that the problem is caused by the load sensing proportioning valve which does not put proper braking power on the rear wheels? My LSPV cannot function properly as it is tied to the carosserie, 30cm above the rear axle, but I am in Cameroon and it is difficult to find someone to fix it...

Its highly likely that is a part of the problem, but you cant even begin to diagnose it until its fixed

 

[ALEXY]

my lj has very snappy brakes after I start the engine, five minutes later and few brakes and the pedal feels just as hard, but the braking efficiency is clearly reduced. I cannot lock the rear wheels. fees like I have grease /water on the brakes.
is it likely to be the lspv as well?

 

[Csaba]

Its highly likely that is a part of the problem, but you cant even begin to diagnose it until its fixed

Many thanks! The mechanic told me as long as it is put this high it will always put maximum pressure on rear brakes and cannot create such symptoms. I am not so convinced though...

 

[roscoFJ73]

I would at least put it back in its proper position and see if it makes a difference. They don't need max pressure they need the correct pressure