Spongy Brake Pedal

[johno]

Upgraded the brakes on Saturday and bled the system of the old Dot 4 for replacement with Dot 5.

Decided (badly) to drain the system complete to get all the old fluid out before filling back up with new fluid. Since bleeding the system and rebleeding the system I am left with a spongy brake pedal. The car stops but I am not making full use of new brakes at all.

I reckon I may have knackered the master cylinder as these do not like to be emptied of fluid completely and refilled. Will try and rebleed system at the weekend but wondered whether anyone had any other ideas.

Was bled by Easiblled kit, longest location first etc etc until no air in the fluid etc etc.

Any ideas ?????

Additionally is there anyone out there (Leebee & Peter) that has got or has had the big brake upgrade kit from Tower View using the existing calipers but taking the discs out to 285mm and can confirm to me the pad location onto disc. Just seems a little inefficiect to me with some of the pad overhanging the outer edge of the disc. Can't see any other way it could work due to tolerances available for the bracket etc etc.... Any info ????

Cheers

Mark

[GreenV8s]

quote:Upgraded the brakes on Saturday and bled the system of the old Dot 4 for replacement with Dot 5.

Decided (badly) to drain the system complete to get all the old fluid out before filling back up with new fluid. Since bleeding the system and rebleeding the system I am left with a spongy brake pedal. The car stops but I am not making full use of new brakes at all.

I reckon I may have knackered the master cylinder as these do not like to be emptied of fluid completely and refilled. Will try and rebleed system at the weekend but wondered whether anyone had any other ideas.

Was bled by Easiblled kit, longest location first etc etc until no air in the fluid etc etc.

Any ideas ?????

Additionally is there anyone out there (Leebee & Peter) that has got or has had the big brake upgrade kit from Tower View using the existing calipers but taking the discs out to 285mm and can confirm to me the pad location onto disc. Just seems a little inefficiect to me with some of the pad overhanging the outer edge of the disc. Can't see any other way it could work due to tolerances available for the bracket etc etc.... Any info ????

Cheers

Mark

Now you mention it, I seem to remember when I had the 285mm conversion, the pads overhung the disc by about a mil. I assumed this was because I had the first ever experimental one, the spacer dimensions were off slightly. If it's any help, you can move the calipers quite a long way by slackening off all four mounting bolts and pushing the caliper in while you tighten them up again - I used this technique to tweak the caliper position to miss the rotor and rims for the current 300mm version.

Don't know about the other problem, either one of the seals has gone on the master cylinder as you say (so you're basically down to one circuit) or more likely IMO you've got some air trapped somewhere. Maybe inside the acceleration valve on the top of the driver's footwell? Do all the calipers have the bleed nipple at the *top*?

[johno]

The bleed nipples are at the top. I will rebleed it this weekend probably using the pedal instead of the Easibleed kit and see if it makes any difference.

As for the overhang it is 6mm at the middle of the pad which is 15% of the of the total width of the sweep area. I will try to undo the caliper bracket bolts and move them around.

In fact I am quite sure the spacers I have (like the dampers) are off your car aswell !!!!!!!!!!!!! Any other cast offs going Peter ???

Mark

[GreenV8s]

quote:
The bleed nipples are at the top. I will rebleed it this weekend probably using the pedal instead of the Easibleed kit and see if it makes any difference.

Aha, you didn't bleed it using the pedal? Depending which master cylinder you have, the reservoir passage is quite a long way down the cylinder, potentially leaving an un-bled volume by the piston.

quote: As for the overhang it is 6mm at the middle of the pad which is 15% of the of the total width of the sweep area. I will try to undo the caliper bracket bolts and move them around.

Crikey I don't remember it being that far out. I wonder if your uprights are the same dimensions as mine were. Did Tower View fit them, or just supply them? Surprised if Dave fitted them that far out, sounds to me like the spacers have put the calipers too far out. Fancy trying some new 290mm rotors on it?

>> Edited by GreenV8s on Monday 8th April 22:31

>> Edited by GreenV8s on Monday 8th April 22:31

[Dave_H]

Mark,

I've found this on some cars that the Easibleed kit doesnt do the job when all the fluids been drained.

I recrenlty had the same on my MGs clutch slave cylinder.

You'll proberly find you'll need to do a pedal bleed then use the kit after that to get the pressure right up.

Cheers,

Dave.

[roulli]

The Easybleed is not the one with the relieve valve, where one needs just to pump, is it?
Patrick

[Dave_H]

quote:
The Easybleed is not the one with the relieve valve, where one needs just to pump, is it?
Patrick

Patrick,

It's a one man bleed system with a sealed container of new fluid with a pipe coming off it with a screw top that connects to your brake/clutch master cylinder (there's an assortment of screw top sizes for most makes) The container also has a pipe that attaches to the valve of a spare wheel tyre. You set the tyre pressure at about 22-25 Psi, connect it all up and when you open the bleed valves on the brakes/clutch the tyre pressure forces the air out of the system and new fluid in.

The kit cost about £10-12 in the UK I think.

Cheers,

Dave.