terrys6t8roadster

I installed wilwood d-8 forged calipers master cyl, bias valve. I have bleed at least $$150.00 worth of wilwood brake fluid in this thing and when using this car @ Elkhart Lake I can go about 2 laps and when I come off the long straight away and apply the brakes the pedal is @ 50%. I've bench bled this master countless times and gone around all the wheels and let sit for a day and pedal starts out great and then goes south under heavy braking (also using Hawk pads) Anyone else experience this? I have talked to Wilwood and they have been very good @ trying to remedy this but problem still persists. If anyone has had this problem in a roadrace application,any help would be appreciated Not ranting,just want this problem rectified

Priya

I was reading about Wilwood calipers the other day, not sure of the specific model, but on some of them the calipers have to be loosened and tilted upwards to bleed properly.

terrys6t8roadster

Been there, done that numerous times Thanks

Priya

Sorry I couldn't help.

zwede

Ok, so the pedal goes soft and spongy. What happens next? Do you let it sit and it's back to normal? Or will it be crap until you bleed it, and then it works again?

vette427-sbc

when the pedal goes to 50% do you mean it will go half way down? Or you get 50% of braking under full pedal pressure?

Ive had my Hawk pads fade pretty good on a track day before...

my 76 ray

Excessive heat can cause brake fluid to boil and result in a spongy brake pedal. Make sure you don't have your brake lines too close to headers or other sources of high temps.

redvetracr

maybe you just have a bad or a wrong size master cylinder...but I`m curious what kind of lap times are you turning to where you are losing your brakes in two laps?

tracdogg2

This sounds more like a runout problem. Wilwood does not use springs behind their pistons. A small amount of runout will cause the pistons to be pushed back into the bores at high speed.
Mike

terrys6t8roadster

it is crap sometimes,I did an auto cross crap braking every time park the car pump the pedal comes right up stays there until turn 2 or turn 3 then half way to twothirds down .Not very trustworthy.

terrys6t8roadster

It is not pad fade, pedal height varies down to just off the floor to maybe halfway requiring 2 to 3 pumps to get braking .Nerve racking when you are trying to slow from well fast. Thanks tr

terrys6t8roadster

worked with wilwood and spec the master cyl 1 inch bore manuel brakes. Just over 2 min 50 sec. Ordered 18 in wheels for slicks
maybe wont need brakes. tr

terrys6t8roadster

Great minds think alike. The next reply , installing residual check valves might be the ticket.thanks.tr

terrys6t8roadster

this is I believe the correct action to take . I'll add the part numbers to my list. thankstr

terrys6t8roadster

thanks for the bleeder tip.I even went as far as changing the castle nuts front spindles to elimanate the play. thankstr need to check with wilwood for 1/4in line check valves, part #s I first looked up were for 3/16 lines.

terrys6t8roadster

I checked wilwood site they only offer 3/16 line size valves and until you get to the tees the line size from the master is 1/4 ". I think the reduction to 3/16 would hampper the proper volumn reaching the caliphers. Which brings up the question of where to mount the valves. The wilwood caliphers that I have ,have the inlrt port in the middle on the inside with offset trailing arms the upward suspension travel ,the rubber stop ,the clearance is 1/8" not allowing for anything larger in diameter than the hose. In the front driver side tee to hose mount the steel line is only 3" with a 90 degree bend then the flex line to calipher. So now for my stupid question where do the valves get installed? at a loss. thanks tr

terrys6t8roadster

Bored, thought I'd look at some of my old threads and I see that I never passed on the info that corrected this problem. 'Rodeck350+ gave me the idea of splindle flex being the problem. After some research the realization [ the Ford light bulb came on] mine is a 6t8 -A SMALL SPINDLE- same as the 65 to 67, 69 and up got larger spindles hubs. So there is the solution, start pricing parts -ouch. Just so happens 1 day I'm checking out the Chicago Craig list of corvette parts and someone is selling some front rotors from a 1975. Open up the add and the spindles and hubs are connected to the rotors for $45. How could I go wrong. Installed them a few days later. Got used to the trustworthy braking at the Milw Mile with the SCCA. Next summer at R/A had my best times, just over 2min 38 secs. Now just to give some perspective to the issue the track record, I think the drivers name was Franchiti and his time was just over 1min, 21secs on a 4.08 mile track with 14 corners in an Indy car. That's averaging over a 120mph, and I thought I was going fast in my 6t8. T

69ttop502

Nice, always good to see the solutions to these problems!

bjm

Glad you figured out the braking problem but the RA lap record is 1:39 and change. 1.21 I am not even sure is possible. Having trust worthy brakes at RA is always nice.

terrys6t8roadster

Thanks for the correction, still very fast compared to me in my C3. Did I even get the drivers name right? T