Bleed, bleed, bleed, till I got no more bloo... Brake Fluid!

[patrickr]

Howzit guys,

Okay, Im gatvol so this is gonna be short! Iv fixed my leaking side shaft and wheel cylinder, AND replaced brake shoes and pads all the way round. But, no matter how many times I bleed the brakes, the brake pedal is still spongy. Iv done it all! started furtherest from the reservoir, pumped the brakes, opened the bleeder screw till the air bubbles are out, closed it, then released the pedal (with a helper ofcourse ).

The worst is that I have no idea what I am doing wrong! I have followed instructions on websites to the nth degree, but to no avail.

What could I be doing wrong???

[JohanM]

Hello Patrick,

Well maybe it is because the brake master cylinder is also slowly giving in, which means that it would most likely need a new master seal kit...

Also check that on some older models you had to bleed some master cylinders on the brake master itself before doing the routine started furtherest from the reservoir....

If not there might be a problem with the booster itself that is leaking air, or something else...

[Mud Dog]

Patrick, just to be sure that you are doing it right .....

The helper sits and listens to your instructions to "push" and to "release" the brake pedal. Using a 10mm spanner (IIRC) for the bleeder nipples, check that they are all tight (don't over tighten ... just 'nipped up'!). Use a piece of 4mm (ID) clear tube over the nipple that you are about to bleed and let it drain to a bottle or something. Ensure that the reservoir remains topped up at all times throughout the bleeding process ... if it gets low it may suck air into the system again. Tell the helper to depress and hold (not pump) the brake pedal ... open the nipple ... close the nipple ... tell helper to release the pedal ... tell helper to depress and hold (not pump) the pedal ... open the nipple ... close the nipple ... tell helper to release the pedal. Repeat .... repeat ... repeat until the brake fluid flows in the drain tube without there being any bubbles visible anymore. make sure the nipple is tight, remove the tube and go to the next one. It's important not to forget to check the reservoir level regularly throughout the process and keep it topped up. You will most likely need a 500ml bottle of brake fluid or even more to get rid of all the bubbles and any old dirty / yellow fluid in the system .... you will use a lot on the first (furthest) wheel.

If the brakes are still spongy after this ... then there is another problem, and as Johan says, do the master cylinder seals.

[patrickr]

Ya Johan, I think you may be right. I just spoke to my Dad, and he thinks it might be something like that.

Andy, we tried just pushing in the pedal, but it just bottoms out, and so started "pumping" 'cause well it gave a bit of pressure. Could this be my problem?

Let me just point something out- with the engine off, after 3 or 4 "pumps" the pedal becomes hard, like it was before I changed things. When I have the engine on, the pedal always bottoms out, giving a like whoosing sound. Does this help in any way?

[conversion man]

The easy way is to first remove the pipe from the master { unscrew the thread }.Then hold your finger lightly over the hole where you have now removed the fitting . nOWSLOWLY pump the master allowing the air to go past your finger but preventing air from getting sucked in . Do this until cleen fluid comes out without any air ,now put a piece of rubber pipe over the pipe that you screwed out of the master and put the end in a bottle of brake fluid .Now open the bleeding screw at the wheel and blow the bottle lightly with a compressed air till fluid comes out the bleeding screw . Close the screw reconnect the fitting at the master and bleed it thru one more time .

[patrickr]

Hi Fana,

I don't really have compressed air so ya. Surely doing the whole compressed air with the bottle is pretty much the same as bleeding the brakes? Maybe I don't fully understand you?

And how would I get that screw back onto the master cylinder without getting air into the brake lines again?

[conversion man]

You will see that after doing the master the fluid wont run out of itif you dont press the pedal . The idea is the to get the pipe full of fluid with minimum air in it . So if you fill the pipe from the top and then close the bleeding nipple the pipe is full and the little air you get in now when you put the fitting back in the master will bleed out easy .The reason for doing it like this will become clear when you do the first step .You will feel that the master sucks instead ofpush when it is full of air .Give me a ring on 0837521655 and Iwill explain .