Brake pedal travel Options

[lsintampa]

914/4 75 2.0

Just installed new ATE brake master from PMB - the one for the 914/6

I use a pressure bleeder and have gone around about five times, first bleeding both top and bottom bleeders (RR, LR, LF, RF) then just the top ones.

Had some weeping out of the RF bleeder overnight, so I bled them again - about three more times.

No leaks that I can see, but pedal pressure is great with the pressure bleeder on, yet when I remove it, pedal pressure is OK, but the pedal travel is a bit much.

I've no 914 seat time (yet), so I'm not sure if that amount of pedal travel is normal or not.

I did tweak the rear pads, but I did it by feel... in other words I tightened up both piston until they were engaged and holding the rotor, then just backed off a bit on both sides to relieve the pressure.

Anyway, it appears I have decent brakes, just a bit more pedal travel then what I'm used to.

Thanks,

Len

[Eric_Shea]

Do you have new seals in your calipers (freshly rebuilt)?

[lsintampa]

Do you have new seals in your calipers (freshly rebuilt)?

Yes, I forgot to mention that the seals are all new.. I rebuilt the calipers just days ago.

[Eric_Shea]

SOP

So now you need to bed the pads and season the seals. In a couple of weeks the pedal will begin to come up. Especially the 19mm. Should be nice and firm once the seals are broken in.

Follow these instructions 2-3 times:

http://www.pmbperformance.com/bedin.html

(check the last paragraph) New seals are aggressively pulling your pistons back into the caliper causing a larger than normal gap between the pad and the rotor. This is contributing to the low or soft pedal feel. Once the seals begin to break in (the heat from the bedding cycle helps this) your pedal should come up.

[lsintampa]

SOP

So now you need to bed the pads and season the seals. In a couple of weeks the pedal will begin to come up. Especially the 19mm. Should be nice and firm once the seals are broken in.

Follow these instructions 2-3 times:

http://www.pmbperformance.com/bedin.html

(check the last paragraph) New seals are aggressively pulling your pistons back into the caliper causing a larger than normal gap between the pad and the rotor. This is contributing to the low or soft pedal feel. Once the seals begin to break in (the heat from the bedding cycle helps this) your pedal should come up.

Well that is going to be a while... motor is still out, lots of stuff to do yet.

Assume the process can wait a while.... uh there isn't much of a choice!

Thanks Eric!

[tomeric914]

Well, it's taken me 3+ years to get the pedal I want. New 19mm master cylinder? Nope, didn't do it. Rebuilt calipers? Nope didn't do it. Bedding of pads or maybe knockbacks that are to aggressive? Meh, could have been.

I thought that possibly the push rod was not adjusted correctly and holding the master cylinder piston in slightly, so I adjusted it to clearly have some play. No help.

I bled with a power bleeder for the first time this year and it made no difference before the first track event this year. However, after the event, I replaced the front pads after (obviously) expanding the caliper pistons. Ever since then I have had the pedal I have always wanted.

So what the heck was the reason? Possibly garbage in an internal circuit somewhere that got backflushed or some mystery bubble trapped in the line somewhere?

[Cap'n Krusty]

Don't set the rear pad clearance by feel. Use an .004" feeler gauge. Make sure the rotors are held tightly against the hubs and check the clearance all the way around. Set the pads at the tightest point. Check the freeplay at the pedal pushrod, too.

The Cap'n

[wndsrfr]

Well, it's taken me 3+ years to get the pedal I want. New 19mm master cylinder? Nope, didn't do it. Rebuilt calipers? Nope didn't do it. Bedding of pads or maybe knockbacks that are to aggressive? Meh, could have been.

I thought that possibly the push rod was not adjusted correctly and holding the master cylinder piston in slightly, so I adjusted it to clearly have some play. No help.

I bled with a power bleeder for the first time this year and it made no difference before the first track event this year. However, after the event, I replaced the front pads after (obviously) expanding the caliper pistons. Ever since then I have had the pedal I have always wanted.

So what the heck was the reason? Possibly garbage in an internal circuit somewhere that got backflushed or some mystery bubble trapped in the line somewhere?

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