Front calipers don't release

Suspension, including wheel, tire and brake.
CP
Posts: 67
Joined: 19 Jul 2003 19:13
Location: Port Coquitlam, BC, Canada

Front calipers don't release

Postby CP » 23 Aug 2017 21:01

So I had this issue rear its head tonight. It appears the front calipers do not release. This happened after about 15 minutes of driving. The are ZX calipers and I have a new master cylinder installed. The pedal was hard as a rock when they were locked on. I had to release the pressure with the caliper bleed screw. The brake lines do go through a Wilwood proportioning valve if that has any bearing. I have verified the plumbing is correct, front to front and back to back.

Looking for clues as we are trying to make the show Sunday.

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Byron510
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Posts: 11686
Joined: 01 Jul 2003 23:06
Location: Maple Ridge, BC

Re: Front calipers don't release

Postby Byron510 » 23 Aug 2017 23:44

The problem is simple, the rod leading from the pedal to the brake master is too long. Shorten the adjustment back so there is a little free play.

What's happening is that the BMC pistons are not full uncovering the compensation port, and your brakes can only pump up and not release.

Do this and you're good to go.

Byron
Love people and use things,
because the opposite never works.

CP
Posts: 67
Joined: 19 Jul 2003 19:13
Location: Port Coquitlam, BC, Canada

Re: Front calipers don't release

Postby CP » 24 Aug 2017 06:57

Thank-you, my project for tonight.

CP
Posts: 67
Joined: 19 Jul 2003 19:13
Location: Port Coquitlam, BC, Canada

Re: Front calipers don't release

Postby CP » 25 Aug 2017 07:31

Looks like problem solved. Probably had to shorten the pushrod 3/8".
Thanks

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Byron510
Moderator
Posts: 11686
Joined: 01 Jul 2003 23:06
Location: Maple Ridge, BC

Re: Front calipers don't release

Postby Byron510 » 25 Aug 2017 07:59

Perfect - that'll do it.

So you good to go for this Sunday's All Japanese Classic at Waterfront park in North Vancouver?

Byron
Love people and use things,
because the opposite never works.

CP
Posts: 67
Joined: 19 Jul 2003 19:13
Location: Port Coquitlam, BC, Canada

Re: Front calipers don't release

Postby CP » 25 Aug 2017 11:12

Working a couple of other small issues but should be there.

Thanks again


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