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Brakes going soft

Posted: Sun Nov 12, 2017 5:49 pm
by chuckput
What I have: I have Jamar disc brakes on all four corners - 4-piston on the rear, 2-piston on the front. Master cylinders are Wilwood 3/4-inch bore, split (front/rear) master cylinders, reverse swing with remote reservoirs.

Issue: If my car sits for an extended period of time (the last time I drove the car was at the Night Run August 19th) I lose firmness in the pedal. While the brakes work for the most part, the pedal goes almost all the way to the floor. I bleed the brakes (using a Motive Products pressure bleeder) and the pedal comes back (I bleed both front and rear - both systems, as it seems to effect both. I have completely inspected all junctions, joints, calipers, and cylinders and find no evidence of leakage. What should I check next? Any ideas about what is going on?

Re: Brakes going soft

Posted: Sun Nov 12, 2017 8:01 pm
by Ol'fogasaurus
I had that problem once; couldn't figure it out but it turned out that one of the flairs I had made was slowly allowing air into the system. No leak showed but after sitting for a long time everything would go south, just like you said. I took the brake system apart to replace the turning brake hancles and cylinders then, when the system was re-connected up it never let air in again. One of the things I did when reconnecting that joint was to carefully align the brake line so it saw level when tightening things up. The nearest thing I can think of is that the tube join to the cylinder's brass adapter might have been at a slight angle so the contact area was off just enough. Go figure!

Re: Brakes going soft

Posted: Tue Nov 14, 2017 7:08 pm
by bajaherbie
Have your wife pump the brakes every day. I am sure she will go for that!

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Re: Brakes going soft

Posted: Tue Nov 14, 2017 11:54 pm
by chuckput
bajaherbie wrote:
Tue Nov 14, 2017 7:08 pm
Have your wife pump the brakes every day. I am sure she will go for that!

Sent from my SM-G920R4 using Tapatalk
Or. . .I could just drive it more!

Re: Brakes going soft

Posted: Mon Nov 20, 2017 2:23 am
by dustymojave
NOW you're talking!