Bleeding brakes
Discussion
I'm going to change the rear calliper on my Audi this weekend but I will be doing it by myself I think. I've got a pressure bleeder, can I use it to do a one man bleeding operation, so pump the pressure up, open the bleed nipple, tube into bottle with some fluid in it and keep open until its just fluid and no air.
I've only previously used the pressure bleeder to force the fluid past an ABS pump on a mates car in the past when it simply wouldn't work the conventional way, but we still pumped the brake pedal that time as there was two of us.
Hopefully the pressure bleeder fits on the cap.
I've only previously used the pressure bleeder to force the fluid past an ABS pump on a mates car in the past when it simply wouldn't work the conventional way, but we still pumped the brake pedal that time as there was two of us.
Hopefully the pressure bleeder fits on the cap.
mickyh7 said:
Don't put more than 20psi into it.
If you do, wear old clothes!
Ha, when we did the Mercedes I pumped it up to the recommended pressure and it didn't do anything so I went a bit more and still nothing, I had to pump it up until I thought it was about to explode before the fluid finally pushed through. Daft thing is we have now bought an icarsoft scan tool so could have done it the easy way if we got one earlier.If you do, wear old clothes!
E63eeeeee... said:
If you're only replacing the fluid in the caliper you can probably just fill up the reservoir before you bleed rather than use a separate bottle. Just keep an eye on the level as you go, don't let it go too low.
Yes I see what you mean, the bottle I was describing was at the calliper end, when ever I've bled brakes in the past I've put a tube on the bleed nipple into a jar half filed with brake fluid, so when the pedal is depressed air pushed out into the liquid but when the pedal is released it only sucks fluid back up the tube. Probably don't need it at all if the fluid is under pressure coming out of the nipple, although it would be less messy.My preferred approach for brake bleeding without help is to connect a clear hose to the bleed nipple and run it up to a container that can be seen from the driver's seat. Because the nipple is the lowest point of the circuit and very slightly pressurised by the head of brake fluid in the hose it doesn't tend to suck air back in. From the drivers seat you can just keep pumping the brakes until the fluid comes out clear. If chasing an air lock with clean fluid you can even dump the hose straight back into the reservoir so no need to keep topping the reservoir up.
scottyp123 said:
E63eeeeee... said:
If you're only replacing the fluid in the caliper you can probably just fill up the reservoir before you bleed rather than use a separate bottle. Just keep an eye on the level as you go, don't let it go too low.
Yes I see what you mean, the bottle I was describing was at the calliper end, when ever I've bled brakes in the past I've put a tube on the bleed nipple into a jar half filed with brake fluid, so when the pedal is depressed air pushed out into the liquid but when the pedal is released it only sucks fluid back up the tube. Probably don't need it at all if the fluid is under pressure coming out of the nipple, although it would be less messy.scottyp123 said:
mickyh7 said:
Don't put more than 20psi into it.
If you do, wear old clothes!
Ha, when we did the Mercedes I pumped it up to the recommended pressure and it didn't do anything so I went a bit more and still nothing, I had to pump it up until I thought it was about to explode before the fluid finally pushed through. Daft thing is we have now bought an icarsoft scan tool so could have done it the easy way if we got one earlier.If you do, wear old clothes!
Eezibleed used, under 20psi off the tyre according to the gauge used before connecting it.
Reservoir split & fluid from the reservoir & the - full - eezibleed blasted all over the engine bay, underside of the bonnet & both wings.
Rapid application of a hose pipe & fortunately no paint damage resulted.
paintman said:
Saw the result of too much pressure on an old brake m/cyl reservoir a few years ago.
Eezibleed used, under 20psi off the tyre according to the gauge used before connecting it.
Reservoir split & fluid from the reservoir & the - full - eezibleed blasted all over the engine bay, underside of the bonnet & both wings.
Rapid application of a hose pipe & fortunately no paint damage resulted.
Yikes. Bet that was a fraught few minutes. IIRC for some cars you can reduce the need for lots of pressure by applying the brake and wedging it on. I assume it does something to the ABS, no idea if this will be helpful on the OP's car, or is even accurate, just something I read somewhere. Eezibleed used, under 20psi off the tyre according to the gauge used before connecting it.
Reservoir split & fluid from the reservoir & the - full - eezibleed blasted all over the engine bay, underside of the bonnet & both wings.
Rapid application of a hose pipe & fortunately no paint damage resulted.
mickyh7 said:
The Eezibleed wasa Godsend, after years of guessing, when working alone, with a one way valve, a hose and a jam jar!
Still got mine, haven't used it for years but it did a fine job the many times it was used.I bought one way replacement brake bleed valves in the past, made one man bleeding easy.
These days i still do things the old way, takes minutes only needing an 8mm spanner clear tube and jar, Mrs is well trained as the brake pedal operator.
All done and dusted, dead easy with the pressure bleeder. I just got a 2nd hand calliper of ebay for about £30 and fitted that, the hardest part was undoing the brake pipe from the calliper, thought it was going to shear off. Obviously this was the problem.
It did clean up alright but still had slight pitting so I suppose its not worth keeping as a spare.
If anyone's interested in how the electric handbrake works then it couldn't be more simple, a threaded bolt screws and unscrews down a piston that pushes the actual calliper piston towards the brake pads, a 12V motor actuates the threaded bolt.
No calibrating involved in resetting the handbrake, the motor just winds until it clamps the pads to a certain tightness, must measure the current being drawn by the motor. To change the rear pads you can either unscrew the motor and wind the screw back with a torx drive or apply 12V to the motor pins so the motor winds it back and then push the piston back with a calliper winding tool or G-clamp, the piston doesn't need to be screwed back in like some rear pistons.
It did clean up alright but still had slight pitting so I suppose its not worth keeping as a spare.
If anyone's interested in how the electric handbrake works then it couldn't be more simple, a threaded bolt screws and unscrews down a piston that pushes the actual calliper piston towards the brake pads, a 12V motor actuates the threaded bolt.
No calibrating involved in resetting the handbrake, the motor just winds until it clamps the pads to a certain tightness, must measure the current being drawn by the motor. To change the rear pads you can either unscrew the motor and wind the screw back with a torx drive or apply 12V to the motor pins so the motor winds it back and then push the piston back with a calliper winding tool or G-clamp, the piston doesn't need to be screwed back in like some rear pistons.
mickyh7 said:
I've just replaced my brake fluid on an A7.
How long do you think that would have taken using Gravity?
Couple of days perhaps!
Really, why post this nonsense.
The thread was about bleeding one caliper....and gravity can be viable.How long do you think that would have taken using Gravity?
Couple of days perhaps!
Really, why post this nonsense.
Not about replacing the fluid in the entire system which is a totally different scenario
Yes, there is some nonsense here.
Slight problem after replacing my calliper, the brakes were still sticking for a short while but not now it seems. They were fine when I first did them but half way through a journey they were definitely binding, I didn't need the brakes to slow down at traffic lights and the MPG dropped to below 30 when its normally well above 40. you could even smell how hot they were.
However on getting out any smell was coming from the front wheels and not the back. The brakes were fine for the journey home though. Could the pressure bleeder have upset the front brakes in any way. I've not topped the fluid up yet as I'm putting new pads in at the weekend and the level is still ok as it is.
However on getting out any smell was coming from the front wheels and not the back. The brakes were fine for the journey home though. Could the pressure bleeder have upset the front brakes in any way. I've not topped the fluid up yet as I'm putting new pads in at the weekend and the level is still ok as it is.
Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff