Bleeding the brakes

[Alice71]

Just fitted the brake pipe kit from just kampers onto my van. Topped up the header tank with dot 4 and me and the mate have bleed the system starting with the furthest wheel away working back to the nearest wheel to the tank. There are no leaks and no air comin from the bleed screws my only problem is the brake pedal is spongy and heads to the floor. Anyone got any ideas of the problem I have any help would be much appreciated

 

[sparkywig]

Try bleeding at the master cylinder.

 

[Alice71]

We tried that aswell but no joy

 

[Trikky2]

Have you also bled the compensator valve between the MC and the rear brakes?

 

[Whistler]

May or not be of no help but have you taken the calipers off at all? I out my new I rd on the wrong sides so the bleed valves were at the bottom. Swapped em over and hey Presto!

Also, I recommend one of them pressure system bleaders.

 

[Alice71]

I purchased one of those eezybleed kits and tried again tonight. They work good I have brake fluid at each bleed nipple and at the master cylinder slowly I'm gettin a brake pedal but just not perfect. I'm now thinking the problem must be the master cylinder the camper has lay outside for 3 years without turning a wheel. Then I bought it 2 and a half year ago I think the seals must be burst inside. The pedal is soft until the last inch before the floor and I'm thinking the fluid must be passing the seal.
Anyone have any thoughts on this before I buy a new one
Cheers

 

[Moseley]

Are your brake shoes properly adjusted all round?

Symptoms of a failed master cylinder are usually that you get a sinking brake pedal after pumping it a few times rapidly and then holding the last pump.

If the above is ok, and you still have air in the system, the master cylinder could be drawing air in as I suspected mine was a while back. My symptoms were that the rear brakes had streams of small air bubbles in the fluid, despite bleeding litres of brake fluid through the system.

 

[Alice71]

I have brake shoes on the back and disks on the front and i have tried adjusting the rear shoes. The system seems to be working as i can turn all 4 corners using my hands with no pressure on the pedal but when the mate puts pressure on the pedal all 4 corners lock solid. But pedal is soft for some reason.

 

[Moseley]

What happens when you do the pump test on the pedal?

 

[Alice71]

Done the pump test tonight for about 10 pumps each time the pedal just continues to be soft and carries on down to the floor. On the master cylinder there looks like a bolt in it on the top is this a bleed screw or has this got anything to do with my problem.

 

[Moseley]

It sounds like if you can't get the pedal to stiffen up by rapid pumping (ooh-err :lol: ) then your master cylinder is not the problem, and you just have air trapped somewhere in the system, or the shoes aren't properly adjusted. As a quick check, I'd tighten the rear shoes so that they are just touch the drums and see if that improves the pedal feel. If not, it suggests air somewhere.

Are you getting clean fluid out of the nipples when bleeding, or are there air bubbles present in the stream?

The bolt on the top of the master cylinder I'm thinking is the one that holds the front brake plunger in place - you remove it to disassemble the MC.

 

[privatejobs]

when you replace all the pads and shoes for new the pedal will feel spongey till the brakes bed in and harden

 

[Alice71]

I will give your sugestions a try over the weekend when the fluid is coming out its solid no trace of air bubbles.
Thanks for your help mate.

 

[Alice71]

Adjusted the brake shows so they were just touching and no more rebled the system again and brake pedal is becoming better. Because I'm used to modern vehicles and I bought the camper as a project I don't really know how the pedal should feel. Should it be similar or the same as a modern car or am I thinking these brakes are no good when actually there ok.

 

[Moseley]

Adjusted the brake shows so they were just touching and no more rebled the system again and brake pedal is becoming better. Because I'm used to modern vehicles and I bought the camper as a project I don't really know how the pedal should feel. Should it be similar or the same as a modern car or am I thinking these brakes are no good when actually there ok.

Sounds like they might be ok then. Is the pedal actually hitting the floor when you push hard on it? In reality they shouldn't feel much different to a modern car when the engine isn't running. There should be a point as the brake pedal descends where you feel the shoes contact the drums. The pedal at this point should not easily move much further - any sponginess from there would indicate that there is still air present.