Braking problem after WOT

[Boss75]

So I've noticed something interesting. I've been doing a little racing lately and when I do a hard run from 0 or 30 to about 100, my brakes feel shot when I try and stop afterwards. It also kinda feels like I have a flat or that my rotors are incredibly warped because the steering wheel shakes back and forth real bad. Once I slow down and work the brakes a bit it quits and braking returns to normal.

Does anyone have any clue what this is? The only thing I can think of is that after the WOT pull the power hasn't returned to the brake booster or something. Hell I'm mostly clueless about this problem. I'm very stumped. Any help is appreciated. :burnout:

 

[01rdcobra]

i get the same problem.

 

[V6&V8SHO]

I know that with my stock cobra rotors and pads braking above 100mph resulted in alot of fade. Early I switched to Yellow stuff pads and powerslot rotors. No more fade and awesome bite.

 

[brkntrxn]

Swap to a better set of pads and get a replacement set of Brembo blanks if your rotors are shot (you don't need cross-drilled and all that bling stuff). Make sure you bed the pads and/or rotors correctly.

Then, flush all of your brake fluid and replace with a good quality synthetic.

 

[99cobraR]

it may be hard to brake because you're doing 100? lol

 

[brkntrxn]

it may be hard to brake because you're doing 100? lol

A good street brake setup will still lock the tires at 100mph before the ABS kicks. For instance, I put XP10 and XP8 Carbotechs with new Brembo blanks on my 99 this past weekened. After properly bedding in the pads and rotors, the car will lock the front tires enough to chirp them at almost any speed before the ABS kicks in and lets them roll. Now granted, these pads are more for the track, but the premise is the same with a good street pad.

The first thing the OP needs to do is check out his brake fluid. If you can see the fluid is dark just be looking at the master cylinder, then it is old enough to have moisture it and therefore degraded to the point you will feel pedal compression and fade at high speeds.

 

[Smacked_in_ATL]

brkntrxn,

Would you recommend the blank Brembo's or FRPP's cross drilled and slotted rotors? I like the bling.:shrug:

 

[Shinigami]

isnt the Cross drill/slotting to help defeat breakfade/heat?

 

[drptitan]

Heat warped, ford brakes are not the best. If you touch the brakes over 80 really, you will experience heat warping on the rotors and it will cause the jutter.

 

[Boss75]

Swap to a better set of pads and get a replacement set of Brembo blanks if your rotors are shot (you don't need cross-drilled and all that bling stuff). Make sure you bed the pads and/or rotors correctly.

Then, flush all of your brake fluid and replace with a good quality synthetic.

I just recently replaced the front rotors and pads with Brembo blank rotors. I can't remember the pad. What I find so weird about this is it only does it after a WOT pull. I was cruising the highway yesterday and decided to test a little and if I moderately speed up from 70 to about 130 and hit the brakes there's no problem.

Could it be that I just need rear pads and rotors? I've never even replaced the pads on those.

 

[brkntrxn]

brkntrxn,

Would you recommend the blank Brembo's or FRPP's cross drilled and slotted rotors? I like the bling.:shrug:

If you ever plan on doing any driving on an open track at speed (at an HPDE for example), then go with the Brembo blanks. If you just want to look good cruising the streets, then go ahead and get the bling-bling cross drilled rotors to impress the street junkies. Just keep in mind that cross-drilled rotors are prone to cracking at the holes due to the repeated heating/cooling cycles. They also work as an effective cheese grater on your brake pads shortening the life of your pad. Slotted rotors are still an effective rotor and not prone to cracking like the cross-drilled versions, but blanks are recommended by the go-fast crowd if you want to be serious about it. While I will agree that cross-drilled slotted rotors look good behind a deep-dish rim, whenever I see that I instantly know the the owner doesn't know the full extent of what it means to drive their car fast.

Could it be that I just need rear pads and rotors? I've never even replaced the pads on those.

You may have some other issue going on as you mentioned. How many miles are on the car? I'd flush the brake fluid regardless. If it is the original fluid then it is garbage. And I'd at least check the rear brakes and most likely replace them to take it out of the equation. What are they, like $30-50 for a set of Autozone specials?

isnt the Cross drill/slotting to help defeat breakfade/heat?

Back in the day, as in multiple years ago, brake pads needed to "degass" when being used. The holes and slots were used as a method for the gas coming from the pad to escape and not build up between the pad and the rotor surfaces (effectively creating a barrier to your friction surfaces). Current pad technology is much better than it was in the past and this functionality isn't needed any longer. See my note above about cracking on the cross drilled rotors.

edit for spehlin x2

 

[venomnous99]

If you ever plan on doing any driving on an open track at speed (at an HPDE for example), then go with the Brembo blanks.

You may have some other issue going on as you mentioned. How many miles are on the car? I'd flush the brake fluid regardless.

Hey Kevin,

Where is the best place to acquire the Brembo blanks, and which synthetic brake fluid woould you recommend? Thanks man.

 

[brkntrxn]

Ken,

What's up? How were the holidays?

I just bought a set from Tire Rack for $62 each front ($143 for the pair shipped) and $45 each rear ($108 for the pair shipped). Had to do it on two different orders because the rears are on backorder until late January.

As for synthetic, I will have to check when I get home. I am pretty certain I have been using Valvoline synthetic. It is readily available at most places and works well for my experience level. It stays fresh in my car as I flush the calipers and most of the system a week or so before every event. A lot of the more experienced drivers recommend Motul 600, SRF Castrol, ATE, Brembo, Wilwood, etc. The Valvoline has done me right so far, but this year I expect to learn a lot more. I have plans to hit at least 5 HPDEs in the next 5 months, so the stresses on the car will really start showing me the next areas to focus on.

 

[venomnous99]

Ken,

What's up? How were the holidays?

I just bought a set from Tire Rack for $62 each front ($143 for the pair shipped) and $45 each rear ($108 for the pair shipped). Had to do it on two different orders because the rears are on backorder until late January.

As for synthetic, I will have to check when I get home. I am pretty certain I have been using Valvoline synthetic. It is readily available at most places and works well for my experience level. It stays fresh in my car as I flush the calipers and most of the system a week or so before every event. A lot of the more experienced drivers recommend Motul 600, SRF Castrol, ATE, Brembo, Wilwood, etc. The Valvoline has done me right so far, but this year I expect to learn a lot more. I have plans to hit at least 5 HPDEs in the next 5 months, so the stresses on the car will really start showing me the next areas to focus on.

Holidays were spent with in-laws, I will leave it at that.Thanks for the info... Really want to make it out to some events, but with school coming up gots to see what the schedule looks like...If not it may be a couple of years before I get out, as of right now I am looking at every Saturday till December 2010 possibly. But if not, i will see you at Carolina Motorsports and VIR...:rockon:

 

[SnakeBit]

I don't know enough about the system, but maybe someone who does will chime in.

Could it have anything to do with the brake booster? I know it operates off of vacuum, and since it does it after a WOT blast, maybe there is some relation.

 

[3B99SVT]

I know it operates off of vacuum

Actually, our Hydroboost systems use power steering fluid. How does your PS fluid level look Boss?

As far as the steering wheel movement -- does it only do it when you're on the brakes and go away (or at least lessen a lot) when you are lift off the brake? If so, I'd say warpage.

I'm not sure what kind of pads I have in mine (I've only replaced the rear pads so far) but mine actually improve performance after a nice run through the gears and a heavy foot on the brake to get back to "appropriate velocity". The heat makes them stop much better for quite a while.

 

[K2AHollywood]

isnt the Cross drill/slotting to help defeat breakfade/heat?

yes cross drilling especially. The slots add surface area to the rotor to help dissipates heat but more importantly they keep a clean finish on the pad every time they pass so its like getting a brand new braking surface every time. The slotting and drilling help dramatically with brake fade and stopping distance. Unfortunately, Brembo doesnt offer both in their rotors, but Baer makes a really nice one for our Cobras

 

[Boss75]

Actually, our Hydroboost systems use power steering fluid. How does your PS fluid level look Boss?

As far as the steering wheel movement -- does it only do it when you're on the brakes and go away (or at least lessen a lot) when you are lift off the brake? If so, I'd say warpage.

I'm not sure what kind of pads I have in mine (I've only replaced the rear pads so far) but mine actually improve performance after a nice run through the gears and a heavy foot on the brake to get back to "appropriate velocity". The heat makes them stop much better for quite a while.

Brake fluid level is fine I've looked a buncha times. And I'm almost certain it's not that the rotors are warped because I can brake any other time from any speed and the wheel doesn't shake at all.

I'm going to take brkntrxn's advise I think and flush and put new fluid in and replace the rear rotors and pads and see if it helps.

 

[brkntrxn]

As the normal process, start at your passenger rear wheel and bleed until the fluid is clear. Move to the driver rear and do the same. Move to the passenger front, move to the driver front. You are going to go through more than a bottle of fluid, so get several. And DO NOT let the master cylinder go dry during any of this.

 

[3B99SVT]

Brake fluid level is fine I've looked a buncha times. And I'm almost certain it's not that the rotors are warped because I can brake any other time from any speed and the wheel doesn't shake at all.

I'm going to take brkntrxn's advise I think and flush and put new fluid in and replace the rear rotors and pads and see if it helps.

Have you checked for proper torque on your lug nuts? How are your tie rod ends? I'm not saying brkntrxn's advice is bad (I'm just bringing up discussion points) it's just that I think something happening in the rear to shake your steering wheel would also cause your entire car to shake some. Maybe it is?