bleeding brakes

[dsan]

Hopefully someone can shed a glaring mistake I'm making when doing this.

Replaced master cylinder, ensured that everything is connected up and reservoir is full. Got wife to pump the brake 2 times and then keep it pushed in whilst I loosened the top master cylinder bolt. Bubbles came out, as did fluid. Did this a few times until only fluid was coming out.

Moved over to the rear passenger wheel, had wife pump pedal a few times and then whilst depressed, undid valve. Pure fluid came out. Did rear drivers, then passenger and then finally drivers. Thing is, pedal isn't exactly how it should be. There is a still a massive amount of travel.

I did check the adjusters in the drums. locked and then backed off a bit until wheel spun freely.

Am I doing something wrong here?

[Tony Z]

I am by no means a brake fundi but here is my take on it...

travel - do you mean free play or is it spongy?

Free play will need adjustment - surely there is a pedal adjuster on the master cylinder?

Spongy is from the simple concept of having air in the hydraulic system. Dont forget, you changed the master cylinder. If you pump the pedal, it doesnt move any fluid, just compresses it. So if you have air near the cylinder, you need to open the bleed valve and pump until all the oil from the cylinder to the brake has been replaced with fresh oil that was in the reservoir before you started the pumping process. Then when you are satisfied that it is new oil coming out and there is def no air in the line, then close the bleed valve while the pedal is busy being depressed ensuring that there is no air.
I hope that makes sense.

[dsan]

There is more travel than sponge at the moment. I didn't see any adjustment nut on the master cylinder. I'll give it another go tomorrow morning and see how I get on.

[hitlers revenge]

OK. Lets do PART 1 first.

PEDAL FREE TRAVEL.

Get on your hands and knees on the floor next to the drivers seat with the drivers door open.

Depress the pedal very gently by hand. As you are pushing the pedal you should feel a slight knock. This is when the pedal plunger hits the "push button" inside the master cylinder. If this travel, up to the knock is excessive, 5mm or more, you will have to adjust the pedal adjuster.

This you will find this between the pedal and the master cylinder. (at the fire wall)

If you look you will find 2 nuts. One is a lock nut. Undo this one by a turn or 2 or 3. Then adjust the other nut while occasionally checking the free play. Once the free play is 5mm, retighten the lock nut and Wallah, you are done.

PSDo not turn the adjusting nut too far as it might come away from the pedal. And its a bitch to get back in. Not even KJ jelly will work. If you still have no luck with the brakes , I will write PART 2 tommorrow.

[dsan]

Hmmm never noticed that nut before. I only saw the nuts for the master cylinder itself, so will check for the other one tomorrow.

nice one geeza!

[Hloni]

[dsan]

got the one-man kit and that worked well. Still need to adjust the brakes but all good so far.

[Ron&Gill]

I'll do part 2 quick...

I don't believe in those one man kits. I know they work, I just don't like them, they are no fun having a beer with after...

You should open the bleed nipple first, then depress the pedal slowly, not too slowly, but don't go stomping on it. Slow and deliberate, is how I would put it. Then, close the nipple and tell the SC to release the pedal. Do this until there is no more air, and the fluid is clear. Not like tea! Brake fluid is hydroscopic, it attracts water and turns brown and rusts your pipes from the inside. It should be changed out regularly. Start with either rear wheel (they are practically equally far from the master cylinder), then the passenger front, then driver's front.

You should adjust your brake shoes first (because if the gap is too big like it would be if you'd pulled a drum off or something, your slave cylinder seal will pop out and then it all ends in tears.) Adjust each adjuster as follows. Tighten it until it is tight, i.e. the wheel doesn't turn, release it one or two clicks. Do the 2nd adjuster on the same wheel. Do all four wheels. Then go and step on the brakes nice and firmly, and do it again. Stepping on the brakes aligns the shoes accurately to the drum and you'll likely find a bit more room to adjust. Then adjust your hand brake cable. This is last, not first... lots of guys do it first because it's easiest, but that's wrong.

[Hloni]

Thanx for the insight R&G, I am gonna attempt this set-up which you guided us by, will indeed attempt it this week-end.

[Tom Bishop]

Part 2 My Way. (I just had 2 also)

Fit a tubless tyre Valve to a 2L Coke cap.

Remove the Brake Fluid Reservoir Cap, Fill the Reservoir and screw on the 2L cap.

Loosen the brake nipple and install a pipe from the nipple. I loop this pipe about 30cm higher that the slave cylinder. This is to stop any air entering the nipple.

Now attach a Bicycle Pump to the Coke cap and pump the brake fluid until no bubbles flow out the nipple.

Of course, never let the reservoir run out, start Furthest, end Closest and keep on going until no more air bubbles.

Some like their brakes to be pumped by their wife. Others Like to do it by themself.