Author Topic: brake psd renewal (Read 3307 times)

guest2737 · « **on:** January 10, 2013, 06:12:54 PM »

Is it necessary to clamp the brake line and open the bleed screw when winding back the piston, never had to do this on any previous vehicles, any ideas please.

tonytan · « **Reply #1 on:** January 10, 2013, 07:13:35 PM »

no not necessary but its a good idea to unscrew the brake fluid reservoir cap while pushing back the caliper piston just don't forget to retighten cap when job is completed and press brake pedal serveral times to bring it back to normal height, good luck.

guest2737 · « **Reply #2 on:** January 11, 2013, 11:53:02 AM »

Thanks Tonytan,
Thats the normal procedure I've always used it's this bleed procedure I've never come across before.

madasafish · « **Reply #3 on:** January 11, 2013, 01:28:25 PM »

I always open the bleed nipple and clamp the brake line.

If not you risk inverting the master cylinder piston seals... oops new master cylinder... (some cars much worse than others.. Vauxhall?)

It is also far less messy and much easier - using an easy bleed clear tube on teh open nipple to channel fluid into a jar...

guest2162 · « **Reply #4 on:** January 11, 2013, 03:39:38 PM »

As said, it depends on seal design. But, after you push the brake pedal, the master cylinder must re-admit fluid otherwise the brakes would remain on. Fundamental of hydraulic system design.

It therefore stands to reason that a slow low volume fluid flow must be ok, otherwise the car would fail in normal service. I'm no expert having not examined any recent master cylinder seals (last one I reconditioned belonged to a Maxi...) but a slow reverse flow ought to be ok. I'd be wary of clamping any brake hose, as damage could be done - never ever clamp an aeroquip hose, as you will certainly damage it (no regular production car uses them, but they are popular for racing).

I wonder what a dealer does?

madasafish · « **Reply #5 on:** January 11, 2013, 04:21:13 PM »

I agree about clamping older hoses. I clamped a 12 year old Fiesta one: it completely collapsed internally and passed no fluid. had to be replaced. Mind you .. any hose like that is a disaster waiting to happen..

guest1583 · « **Reply #6 on:** January 12, 2013, 08:06:48 AM »

Hi,
nice for this topic around October this year Ive re placed my front brake pads, without opening the the valve but clamping on the brake hoseso have a clear access on the caliper.
The drivers side caliper was straight forward and relatively easy as i pushed the the pistons back, however on the passenger side the piston was really stif and as if wont pull back , by then I have used a biiger c clamp to push the piston back so I can place the new brake pads (ferodo brake pads), it did move but needed abit of force.
It did worry me as pushing the calipers piston back should be smooth will a smaller c clamp and using the old brake pads to push it back. I have noticed there was a leak of brake fluid with the the valve on the other side as i should have forced it, by pushing the piston at the other side, but as i have tighten the nut on this valve leak is gone, and late i have it all flushed in the small garage and re placed the brake fluid as well.