Brake bleeder

I do both as I usually want to flush out all the old fluid.
Regards Philip A

I gave up on mine, kept drawing air via the threads of the bleed nipples and would not draw fluid from the master cylinder reservoir, got a helper (wife) and used the time honoured pedal pumping method.
Been thinking of making a pressure bleeder, was the only way of bleeding some of the aircraft types (mainly bug smashers) I used to swing tools on.
Done by pumping up from the bleeder.
Got plenty of 3 mm ally left over from building the back on the 130. Planning to do the same for the the gearbox and diffs etc.

I had success with a Gunsons ezibleeder, just hook it up to a spare tyre (with maximum of about 15psi from memory) and go and do a wheel at a time.

gunsons ezibleed | eBay

Tom.

When converting my second MGB from LHD to RHD, I had to swap the brakes over as well, complete with new pipes. The bleeder I used had a one way valve on the end of a length of pipe (ball bearing and spring set up). You put that on the bleed nipple with the valve in a jar under some old brake fluid to guarantee no suck back of air, cracked the nipple then sat in the car and pumped the pedal. The only trick was making sure you didn't pump too often and suck air in through the master cyclinder (ie, pump five times, top up the reservoir, repeat). Simple but it worked a treat and I did the entire braking system from dry on my own. I've done similar with just a simple piece of tube but as sure as eggs, you'd get it right and the end of the pipe would come out of the jar.

However, none of that is going to stop me investigating more complex systems seeing my old bleeder died years ago (hmm, that sounds like I'm swearing doesn't it, rather appropriate when talking about brake repairs).

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Originally Posted by loanrangie

My method is similar except only one length of tube and a coffee jar at the end so only one wheel at a time.

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I have been doing my brake flushes like this for years now. I usually use mig wire or string to hang the bottle. As long as the bottle is higher than the caliper, all the air will get forced out when you pump and the fluid will stay in the line so you can see when the old fluid has been flushed through. I wrap thread tape on the bleed nipples first to prevent any air sucking past the threads. Not really necessary though. For peace if mind I also put a small block of wood under the brake pedal so i don't inadvertently push it down too far and stuff the master cylinder seals.

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Originally Posted by Rick122

For peace if mind I also put a small block of wood under the brake pedal so i don't inadvertently push it down too far and stuff the master cylinder seals.

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I didn't know about that one. What's the story?

The usual travel of the master cylinder piston is only small. When bleeding, it is easy to push the piston past where it would normally sit in the bore and if there is any wear or corrosion present it can damage the seals. I usually suck out all the old fluid from the reservoir first and clean out any built up gunk too, otherwise it will just get drawn into the master with the new fluid.

Thanks for that mate. One of the problems with learning from your old man is you usually learn his bad habits as well though in his defence, we did a lot of stuff that technically we shouldn't have been able too.

I've seen it happen three or four times, on two cars the fluid hadn't been changed for a long time and the master cylinders were probably due for a rebuild anyway. Another was a Toyota towmotor routine brake flush and the guy pushing the pedal was nearly putting his foot through the floor pumping it. They went through 3 bottles of brake fluid. The pedal wouldn't hold pressure and on the test drive it was dangerous. Pulled the master cylinder apart and the seals had inverted and were stuffed. It was leading internally.

Scary stuff. Brakes are so stupidly simple and so easy to screw up. I once spent a couple of hours trying to get a Ford Escort's brakes behave and only sort of succeeded (the owner didn't want to spend any money, always a first mistake). I think part of the trick is knowing when to give components to a professional (eg, honing and sleeving a master cylinder) and being patient assembling and bleeding the brutes. Clutches can be as bad as I learned when changing a clutch line on an MGB and then spending two hours bleeding the rotten thing. When things are going right, it's simple, when things aren't ... well ... you need a generous supply of swear words.