Here's the problem: 93 del Sol Si- brand new Porterfield R4-S's, Motul brake fluid, new master cylinder, goodridge brake lines.

After a track lapping day my brake pedal is "soft". The front pads (new R4-S's) were chunked and the piston boot was burned away. The calipers are original.

Should I replace the calipers and the pads? Obviously the front pads got too hot.
I'm thinking this is due to old piston/seals in the caliper not responding as fast as they should.

Any ideas on how to keep this from happening again would be appreciated.


[Modified by delSolLS, 12:43 PM 6/25/2002]


[Modified by delSolLS, 12:51 PM 6/25/2002]

 

R4-S just aren't track pads. Not made for to work in that heat range. Try something like a Porterfield R4, Carbotech Panther Plus or a Hawk Blue. All of those will work.

 

R4-S's are OK for light track duty. If you are really getting on the brakes, they will start to go away. I would definitely check to see if your calipers are sticking. I just got two reman'ed front calipers for my car. They both were sticking. The right was worst than the left. The reason that I am suggesting this is because the boot is burned up. It is a really good bet that the pads are fried. If they look like johng's, they are toast for sure.

 

Replaced both front calipers, front and rear pads (Bendix for now). Flushed and bled the lines with Motive pressure bleeder (not passed 19psi) and "by hand".

Still have low pedal. Brakes work, but pedal travel is alot further.

Brake booster passes Helm's test. I'm stumped, any suggestions?

 

no abs, right?

how much fluid did you run thru the system when you bled it? On my car it takes a full litre to get all the old crap out. Did you bleed the back? Start there.

btw, if you melted your boots you probably need some ducting.

Joel

 

No ABS. Went through 48 ounces of brake fluid during final bleeding. Bled all 4 corners per Helms manual. The only things I can think of causing the problem are: 1)still air in the lines 2)small leak somewhere 3)defective new master cylinder.

Could anything else cause the problem?

 

How many times do we need to say, Porterfield R4S do NOT do well on the track and are literally destroyed after a couple hot laps wasting your money and time.

 

I'm not talking about track lapping right now. I am just trying to get my brakes back to normal on the street. I ripped out the Porterfields and got some Bendix front and rear pads for the street.

I got frustrated and took it to a mechanic today. They say nothing is wrong, just a brake in period for the new pads, calipers, master cylinder and lines I installed. Can this be true? Could a new master cylinder just provide a different feel than the original?

The lower pedal makes it hard to heel and toe, and kind of makes me wary.

I'm going to get some dedicated track pads/rotors for the next lapping session. This board is a great tool and I value the information, keep it coming.

 

Or you "dished" out the front rotors..

Get a micrometer and measure the thickness of the rotor at the edge, middle and inslde near the hub..

If you don;t have a micrometer, use a dial indicator...
If the rotors are dished, means the middle of the rotor surface is worn away or "deeper" than the inner and outer edges... This will cause the pads to flex and create a mushy pedal.. If so, junk the rotors and get GOOD new rotors..Spend about $40 each for rotors, anything else is too cheap and will not seat pads properly. I'd personally use Honda originals..

Also, pressure bleeding is BAD on Honda brakes unless you use a force pressure bleeder (puts pressure from the master not sucking from the wheels,) or use the old, 2 person pump and hold method..

Hope this helps...

 

DAMNIT! Why didn't I read this forum first!

I just ordered a set of R4S pads just 3 hours ago! Damn!

Ohh well, live and learn. Will be done with those by the end of the year...

 

I'm using the Motive pressure bleeder-hooks to the top of the master cylinder.

The rotors are the only thing that hasn't been replaced-would the dishing you speak of cause vibration as well?

 

Depends.. Most of the time no, Usually vibrations are caused by overheating that results in hot spots (blue) or heat checking (hairline cracks). Dishing is usually apparent when you measure the radial runout and find thickness variations but will usually NOT cause a vibration, but will cause a mushy pedal..
Pads that are not BED properly will sometimes cause the same mushy feeling, but will wear in...

[edit..that spelling thing again...twice even]


[Modified by jasyatz, 9:51 PM 6/25/2002]


[Modified by jasyatz, 9:51 PM 6/25/2002]

 

Update: Have brakes, still longer pedal travel. Daily driving this would be ok, but I'm concerned as brakes fade during a track event. Rotors are fine. Running out of options.

Could the parts house new master cylinder be the problem?

Should I buy the more expensive one from Honda, or is their a better option?


[Modified by delSolLS, 12:16 AM 7/4/2002]