I run racing brake pads.

It happens on a/x courses running counter-clockwise.

I always flatspot/cord the right front. Race tires...

today I drove on my street tires and coming down a steep mountain road, left handed turn, the right front locked.

Could this be the inside wheel lifting and the only front wheel on the ground locks?

KT

i have same problem....

i need a corner balance ... whats your problem.

yep the other one is airbraken You're suppose to brake hard before turn in,decreasing brake force as you turn, then transiton to throttle.
I say this as I am sitting in my chair reclined

Ya You should check you're corner balance.

are you braking while cornering????

Add whatever you weigh (no need to post how many 80lbs sacks of motar mix you used ) to the passenger side footwell area. See what it does then on that mountian road...

Curious minds want to know...

Tom

The first thing I do is check the other side. I've had this happen and it has always been air in the opposite caliper, but it could be glazing of the pad or rotor.

I have to bleed my fronts 2 or 3 times over a period of a week or so to get the air out after major work.....S calipers.

I had this problem on AX's (although I'm on a totally
flat layout) until this year when I replaced the shocks.
My 35-year-old koni reds were still being shocks, but
not at all matched to the 21mm torsion bars. New
koni yellow full soft and I can control the front brakes
much better. Of course check all other easier things
and corner weights as well.

How old are the calipers? If they get heated really bad then the seals could be failing and not letting the pistons retract after braking or have gotten goop behind the dust seals. Try pulling the pads in the front and compressing the pistons and try to gauge how much force is needed on each side. I would bet the right side needs more. I made a tool that opens the pistons just so I could feel this since using a big C clamp or something wasn't the best way. When removing the pads, are they binding any at all. I usually grind off all sharp edges and use some synthetic grease on the sliding surfaces so they will not bind. You can easily re-bed the pads when finished. Oh yeah, corner balance to see what kind of weight is on that wheel.

Trekkor, I saw your lock ups at Marina. Typically was unloaded tire as you were going into corners.

Have you tried threshold braking in a straight line to see if you have the same issue?

Hey after all these carting sessions we are used to rear brakes only just unhook the fronts!

Did some testing today on street tires.

After a series of hard braking following a 20 minute twisty tour north Of Calistoga I pulled into a gas station for some temperature data. Under very hard braking the front right locked again.

Left front rotor- 250 degrees/ caliper 125
Right front rotor- 250 degrees/ caliper 125

Left rear rotor - 175/125
Right rear- 186/ 128

After I got home I tested again and all the temps were about 10 degrees lower across the board.

Still with me?
With the front right wheel locking, I'd expect higher temps on that side. Also you'd expect the car to pull to the right with light hands on the wheel. No and no.

I'm confused.
Any ideas?


KT

Your RR looks like it is working hard which maybe enough to to ease up on the RF. ?!?!? Just a guess. Maybe a corner balance thing, but that is diagonally, RF to LR and LF to RR.

did you have it corner balanced yet?

No...


KT

then do that first...

There's a possibility if the calipers haven't been serviced in a while that one side is sticking which will send more pressure to the other side.

Do some brake tests in a straight line on a good flat surface. Not only look for the loclup point but feel is the car pulling to one side more than the other.

All rotors are in good condition? no warpage.
Plenty of life left on both inner & outer pads?
Pad to rotor contact good? ie full contact.

The evidence

These are rebuilt units with new pads, BTW.

I plan on rebleeding the brakes before the upcoming track day.

I have a spare set of good front rotors that I may use.

thanks for the ideas.


KT

By the looks of that picture you are turning or else the car sits REALLY higher on the right? At any rate the brakes shouldn't be on then, you should be accelerating. Have you corner balanced yet?

again.

course was clockwise, so throw that out...

KT

C O R N E R B A L A N C E

No cornerbalance yet

And yes, sometimes I still brake into the turn out of a long straight.

Just thought I'd show the photos from Saturday.

KT

I'm just a clown, but I got a couple of scales and some 2x10's for
levers and got 'er done.

If the corner balance doesn't work, I'm sticking with my shock
theory.

After hard braking, get under the car with a flashlight and look at the clearance between the pads and the rotor on each side of each front rotor.

I'd bet that one piston on your right front is not retracting properly, and is therefore applying more pressure that the other 3 front pistons especially noticable if you are trail braking...

I had a similar experience, and my right front was dragging enough that it caused a spin out in a high speed turn (turn one) after a long straight and moderate braking before turn in. If you find that is so, rebuild the calipers, and while you have the pistons out of the calipers, clean them with some 1000 or finer grit emory cloth, preferably chucked in a lathe. Don't grind them down, just polish them.

One of my pistons was slightly corroded and would hang and not retract, and the little rubber seal was not strong enough to pull it back. If you have new pads in the car the corrosion is probably out near the end of the piston.

Once I polished the pistons, they worked much better, and pad wear on my right front was noticably less, and the little brake fade I had went away.

Good luck with it. Fix it though, because the situation will get worse and can be dangerous to you and your car in a high speed corner.

I agree. I'd better tear the front calipers down and inspect/polish the pistons.


KT

In defense of corner balancing, I posted a while back that I had just done it and afterward the car does not sit level, as a mater of fact if is noticable to anyone looking at it. Before the corner balance I had the car sitting level both front and rear with me in the car and when it went on the scales there was over 300# difference between the right and left front! I was pretty shocked to say the least but I guess it is not how it looks but how it does the foot print.

Where are you, Nathan?

Bring your scales

KT

QUOTE

I posted a while back that I had just done it and afterward the car does not sit level,

Absolutly right John, if all your mechanic / engineer is doing is playing with adjusters & spring perchs this'll create a very noticable height difference at each corner.

I had mine balanced 3 times each time the engineer & I both learned something. Best advice is set the car height before balancing. Adjust in small incriments. If you want to put two turns into one corner, instead but one turn up & one down in the oppsoite corner.

One big thing dynamic corner balancing doens't move any physical weight. To be really accurate think of doing a static corner balance, where shocks & sway bars are locked out. Now move physical items, battery, seats etc to get a more ideal distribution.
When you next do a dynamic balance you should be just finetuning.

HTH
Trev.

I bled the brakes all around once more.

Got a little bit of bubbles out of all 8 bleeders

Problem solved...


KT

JP wins again


KT