Long brake pedal travel after pad change

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Sat 12 Apr 2003 21:20
Long brake pedal travel after pad change - RogerL
The front brake pads on my Astra have just been replaced and although the car stops as normal, the pedal travel seems longer / softer than before. The Haynes manual warns that master cylinder problems can be created by pushing the piston back. How can I check if this is what has happened?
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Sun 13 Apr 2003 00:00
Long brake pedal travel after pad change - Railroad
It is possible to damage the master cylinder on these if you don't open the bleed nipple when pushing the caliper pistons back.

In this case I don't think so because you say the brakes work. If the master cylinder seals became inverted you will have no brake pedal at all.

Try bleeding them. And check how much free play you have on the brake pedal. You should have about ¼" or so. This can be adjusted quite easily at the master cylinder/brake pedal pushrod.
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Sun 13 Apr 2003 02:46
Long brake pedal travel after pad change - Dynamic Dave
I had this same problem on an Astra after a front pad change. Somehow air had got into the brake system on pushing the brake pistons back to accomodate the new pads. In my case, the system needed bleeding and everything was fine thereafter.
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Sun 13 Apr 2003 08:38
Long brake pedal travel after pad change - Andrew Moorey (Tune-Up)
What is happening is that the new pads have got to bed in to the profile of the old discs and you are probably only braking on about 40% of the swept area. Worth bleeding anyway to get some fresh fluid into the system but the pedal should come back anyway with use.
Happiness is a T70 at full chat!
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Sun 13 Apr 2003 12:45
Long brake pedal travel after pad change - RogerL
Thanks for your advice, guys.

I've bled the brakes all round this morning - it's made no difference. When I re-tested, I tried a panic stop from 40. It starts to slew to the right but doesn't slew any more once the ABS starts, although the ABS doesn't feel like normal (normal test not normal driving!).

I'm wondering if I've inverted the master cylinder seal for just one of the dual circuits, leaving the other circuit working normally. I guess a new master cylinder is still the only cure. Presumably a rolling road brake test, like the Mot, would show this up.
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Sun 13 Apr 2003 16:35
Long brake pedal travel after pad change - jcII
I remember hearing that u must remove the cap on the fluid reservoir when changing the pads on the astra. This was, at the time, the new model(mkiii i think) the one that started about a Jreg. Apparently people where damaging the master cylinder when changing pads on this model.
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Sun 13 Apr 2003 20:29
Long brake pedal travel after pad change - Cyd
Let the brakes bed in by braking gently for the first 200 miles after which it should get better as the brake pad surface shapes itself to the disc.
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Mon 14 Apr 2003 09:18
Long brake pedal travel after pad change - Chas{P}
RogerL

Just done the same job yesterday on my 97 Mk3 Astra.

If you have the ATE type caliper it is possible to fit the outer retaining clips incorrectly. This will have the effect of holding the pads off the disc excessively and will cause a longer pedal stroke.

Worth checking that first.

HTH

Charles
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Mon 14 Apr 2003 12:19
Long brake pedal travel after pad change - glowplug
Doubt it's related but just to show how things can go wrong here goes...

My boss had the front pads changed on his E reg Astra estate by a local garage - he needed them doing that day and so couldn't wait for the maindealers. By the time he'd joined us on site in London (180/200 miles) the brake pedal was touching the floor and braking almost non existant. On checking the master cylinder it was empty, further investigation revealed that it looked as if the 'mechanic' had retracted the caliper piston using a pair of pipe grips to compress the piston to against the back of the caliper, however on theses calipers the flexible hose connects to the back of the caliper using a copper washer, so as the piston was forced back into the cylinder the copper washer was crushed. Everytime the brakes were applied an amount of fluid was lost. I believe legal action was threatened but never taken.

Steve.
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Tue 4 Jan 2011 22:37
Long brake pedal travel after pad change - hazdadzo

I had the same problem after changin the pads. Brakes working, but very long travel on the pedal. it turned out the clip was not on correctly,

thanks for the tip! I also suspect that the outer pads are left and right specific. i swapped mine over and they slotted in to place more easily. i think the key is that the brake wear warning spring is at the opposite end to the warning spring on the inboard pad.

brakes now working fine.

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Wed 5 Jan 2011 16:50
Long brake pedal travel after pad change - quizman
Nearly 8 years, is this a record?
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