Brake Experts Read This Plz

[Ric S.]

I have 200 miles on the car and have from day one had brake fluid leaking out of the Wilwood masters. One maybe two leak, the clutch and front brake units. I use their 570 fluid. Everytime I come in from a break-in ride, fluid has collected on the bottom of the cylinder. When I followed Alan's directions to seat the front brakes by going from heavy right pedal to heavy middle pedal, I got a puddle of fluid. Now, the fluid level does not appear to go down much if any...........make sense?? This may be a combo of both cylinders but most of the fluid is on the brake master. Wilwood did not have a good answer but is sending a new cap to test that as a possible cause or solution. Is this just a break-in norm? I have also confirmed the leak is not at the fittings.

????

Thank you, Ric

[Aggressor]

Ric, In 12,000 miles( 7 Years) I have had one Wilwood Master cylinder fail. It failed very quickly and I ended up driving home from a distant car show virtually clutchless in Summer 2006. I don't imagine that you're overfilling the MC's and not allowing for fluid expansion. It would be odd to have received 2 new Masters and both were faulty from manufacture. I understand the Wilwood MC units are very similar to the Girling units used on classic British sports cars and probably share some DNA in the past. With this apparent kinship, I've stopped using DOT3 in favor of Castrol/LMA. I've owned British sports cars since the late 60's and know that Girling was fiercely adamant about Castrol/Crimson being the only acceptable fluid back in the day. I'm now using Castrol/Girling/LMA fluid as Castrol/Crimson fluid is no longer available.

Double check all your fittings, connection points, and cap seals.

-Geary

Or maybe you're just standing on the load pedal too much and raw acceleration/high speed cornering is forcing the fluid up through the cap vent hole. Ya know it's OK just to cruise easy once and a while. Ford FE's, Tires, and Clutches are expensive.

[nolastyankee]

Ric,
When seating pad/rotors there is significant fluid expansion, much more than in normal driving. Remember, the master is handling the fluid expansion for the whole system including the calipers. Need to leave about a 1/2" below the cap to ensure that fluid will not press out the hole in the cap.

You may want to take a look at the underside of the fender directly above the caps. Often in an overfill condition the fluid will shoot out the top of the master cylinder cap (the vent hole is much smaller than the cylinder bore, hence significant pressure through a small opening) and be stuck to the underside of your body.

I recently broke in new pads on all corners and the same thing happen on my drivers side, however, I knew I was borderline on my fill level (too high) but didn't want to pull the wheels back off to bleed again...I was braking, very near pedal fade and poof - white smoke came off the drivers header as the brake fluid level 'self corrected' and burned off on the hot pipes. Once at the 'corrected' level there are no more leaks.

570 is a good fluid. Really sounds to me like too much in the cylinders.

[souzape]

I have had this problem since I first started driving may car and in my case the issue was with properly/carefully securing the caps to the master cylinders. The threads are very coarse and rough and it is extremely easy to get the cap slightly cocked which will cause fluid to weep over the rim. I tried O rings and new caps but nothing will work if the cap is not straight on.

[davebetts]

I experienced the same issue as the last post. The course plastic threads on the cap and the badly casted threads on the cast metal cylinder.are certainly not well machined. I sometimes fiddle for a few minutes to get the cap straight on. It sems on tight but its crooked. You will know when it turns multiple times and seats correctly. Check it out.

[spd4me]

I wounder why they don't put rubber seals on caps. While on subject of maste cylinder, check my new thread "Do math before doing time"