Wilwood disc brakes sticking

Shocks, Springs, Brakes, Frame, Body Work, etc

Moderator: Team

Post Reply
redliner
Expert
Expert
Posts: 777
Joined: Sun Feb 26, 2012 4:07 pm
Location:

Wilwood disc brakes sticking

Post by redliner »

Hey guys, I got my Stude out for the first time this spring and it seems the mastercylinder is not relieving the pressure very well when I let off the brakes. It takes quite a while ( 15 minutes?)for the pressure to be off (as far as turning the tires by hand.) I have A Wilwood M/C with Dynalight 120-6818 calipers on all 4 corners. Will this heal??? I hope cuz I hate messin with brakes. They haveworked fine for 5 years or so. Easy fix? I hate tearing into them....
User avatar
BOOT
Guru
Guru
Posts: 2895
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Wilwood disc brakes sticking

Post by BOOT »

If you open the bleeder do they let up? If so could be bad soft lines
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
redliner
Expert
Expert
Posts: 777
Joined: Sun Feb 26, 2012 4:07 pm
Location:

Re: Wilwood disc brakes sticking

Post by redliner »

BOOT wrote: Mon Apr 08, 2019 9:40 pm If you open the bleeder do they let up? If so could be bad soft lines
I pulled the M/C and sent it back to Wilwood. The brakes would free up when I cracked line at M/C and the M/C is still under pressure.
pdq67
Guru
Guru
Posts: 9841
Joined: Thu Mar 04, 2010 8:05 pm
Location:

Re: Wilwood disc brakes sticking

Post by pdq67 »

Please note this!!

Make sure your M/C pushrod CAN'T fall out if it's piston sticks!

If it does, the pushrod MAY fall out and then you won't have any brakes!

I used a big P/B M/C on my car and fabbed a retainer that holds the pushrod if the piston ever sticks!

Power M/C's have shallow piston holes that the pushrod may fall out if stuck and non power M/C's have deep holes in the piston so the pushrod can't fall out!

Please check this closely!

pdq67
redliner
Expert
Expert
Posts: 777
Joined: Sun Feb 26, 2012 4:07 pm
Location:

Re: Wilwood disc brakes sticking

Post by redliner »

pdq67 wrote: Tue Apr 09, 2019 11:38 pm Please note this!!

Make sure your M/C pushrod CAN'T fall out if it's piston sticks!

If it does, the pushrod MAY fall out and then you won't have any brakes!

I used a big P/B M/C on my car and fabbed a retainer that holds the pushrod if the piston ever sticks!

Power M/C's have shallow piston holes that the pushrod may fall out if stuck and non power M/C's have deep holes in the piston so the pushrod can't fall out!

Please check this closely!

pdq67
I think I did this when I built it but will double check, thanks!!!
62ChevyII
Member
Member
Posts: 75
Joined: Wed Feb 10, 2010 12:33 pm
Location: Wichita, KS

Re: Wilwood disc brakes sticking

Post by 62ChevyII »

Redliner, did you ever figure this problem out? I'm having trouble with my Wilwood Dynalite calipers sticking too...
User avatar
Baprace
HotPass
HotPass
Posts: 1905
Joined: Sun Aug 06, 2006 4:57 am
Location: Henrietta NY 14623

Re: Wilwood disc brakes sticking

Post by Baprace »

redliner wrote: Tue Apr 09, 2019 2:01 pm
BOOT wrote: Mon Apr 08, 2019 9:40 pm If you open the bleeder do they let up? If so could be bad soft lines
I pulled the M/C and sent it back to Wilwood. The brakes would free up when I cracked line at M/C and the M/C is still under pressure.
I think the pushrod to mc needs a little end play, if the rod is too long the mc cannot relieve the brake pressure, you don't need much end play .015 should be enough when every thing is up to temperature. One last item you need a disc brake mc with disc brakes, a drum brake mc will cause the same problems when used on disc brakes.
chimpvalet
Pro
Pro
Posts: 447
Joined: Wed Jun 04, 2014 2:02 am
Location:

Re: Wilwood disc brakes sticking

Post by chimpvalet »

A fellow who hosts technical forums over on Yahoo has had big trouble with Wilwood M/C's and puts it down to use of plastic for the retainer on the stem of the internal check valve. IIRC his problem was complete loss of pedal which he attributed to the soft retainer flex causing the stem to cock in bore and thus preventing the check valve from seating at the fluid reservoir entry port. He machined up that retainer "hat" in brass as a solution. FWIW

Cheers
HS Nova
Expert
Expert
Posts: 517
Joined: Sat Sep 21, 2019 3:41 am
Location:

Re: Wilwood disc brakes sticking

Post by HS Nova »

Gentleman, you are aware the Wilwood has a recall on some master cylinders. You might want to call them first and see if your master cylinder is affected.
chimpvalet
Pro
Pro
Posts: 447
Joined: Wed Jun 04, 2014 2:02 am
Location:

Re: Wilwood disc brakes sticking

Post by chimpvalet »

Was not aware of a recall, thanks for bringing that to our attention.
HS Nova
Expert
Expert
Posts: 517
Joined: Sat Sep 21, 2019 3:41 am
Location:

Re: Wilwood disc brakes sticking

Post by HS Nova »

Post Reply