Da Mail Man

greetings all,

i have a contiuing problem with my 88's brakes. they just don't grab for $_it!...fred flintstone had better brakes. i have;

1)... replaced all pads with recomended pads,
2)... flushed + bled all brakes, lines, etc more than 4x's already,
3)... replaced brake hoses with stainless,
4)... good known master cylinder,
5)... have had on 3 other m/c's and no difference in braking,
6)....calipers don't appear to be hanging up,
7)....used a "miti-vac" to draw vacuum on brake booster and check
valve and it "held",
8)... rotors are fine, no scores, etc.,
9)... broke in new pads as recomendend,
10)...no spongy brakes or hard pedal or excessive pedal travel,
11)...correct brake fluid,
12)...abs system (test) initializes properly when backing, etc
13)...no "hissing sound" from booster,

i am running out of ideas here! i imagine that if the abs were bad, it would through some codes but, none "thrown"....

...any ideas or other test methods?...thanks!

c4cruiser

You could have a glazed surface on the rotor face from a previous brake pad compound. You didn't say how new the rotors are but you might want to have them turned just enough to get a new surface on them. While the factory service manual doesn't recommend turning the rotors, you might give it a try. Re-bed the pads after turning or replacement.

Replacement rotors are not that expensive anyway so the cost of new rotors may be worth doing. It sounds like you have pretty much gone thru the rest of the system.

Da Mail Man

........thanks for the reply

re rotors;......."8)... rotors are fine, no scores, etc.,"
(i am unsure how new or old the rotors are)
would "glazed rotors make that much of a difference in braking?

Aardwolf

" how 2 check 88 abs? "

Drive around 40 MPH, stand on the brake pedal with both feet. You should hear a rapid sound (BIZT! BIZT!) similar to what you hear when the ABS first initalizes. That whirling sound behind the drivers seat, when you first start driving. You'll know it if it's working! Also pressing the pedal very lightly in slippery terrain will activate it. I drove across my driveway in snow once this winter moving the car out of storage because I needed the room for a bit. The ABS was funny it activated so much!

Da Mail Man

thanks for the reply. i can hear it when i back out of the driveway so, imagine it is working. i spoke with a guy at a shop late this afternoon. he believes that it is my rotors that is giving me the crappy, almost non-existant braking.

he believes the rotors are glazed as they are very "shiney". there is no place around me that turns rotors anymore due to strict epa guidelines so, he sdvised with instructions as to how i can break the glaze on my rotors and pads which i will try by the week end. the abs is throwing no codes at all at this time either.

c4cruiser

Most of the shops around here have brake lathes and where I work, we even turn new rotors to insure they are not warped. I don't know what "EPA Guidelines" he is referring to but turning rotors and drums is still a common part of brake overhauls.

But most rotors are manufactured with little room for turning down the thickness. Rotors are stamped with a value that represents the minimum safe thickness and reputable shops will not turn rotors and drum if the are close to the minimum spec. Stock type rotors are cheap anyway.

Da Mail Man

i was surprised to be told what i was told. i thought it was for liability purposes. he explained that the epa guidlines for turning rotors (short title) was (in part) that the lathe must be in a separate room and completely closed off from any other room. there must be some sort of a dust collection or filtration system in place and the "users" must wear protective gear (glasses, filter masks, etc).

he explained that while turning the rotors, brake dust - particles, imbedded or otherwise, would be released into the air, etc etc etc. .
three local shops told me this and the last shop "sealed" it for me.

i know that there some dealers whom probably turn rotors and some remaining shops but, i am unaware if there is a time limit for them to come into compliance.

i plan on writing the epa and asking for not only clarification (if any needed), but, a copy of the directive of such restriction(s)....

Insane1

They don't have any rules like that in Calif. and we are one of the most strictest when it comes to stuff like that. I can go down to my local Kragen and get rotors/drums turned for $5 a piece. And they just turn them behind the parts shelves.

c4cruiser

Back when brake pad and shoes contained asbestos, there were some concerns about the asbestos dust being breathed in. But asbestos has not been used in brake compunds for years.

In any event, EPA Guidelines are federal requirements and all 50 states would have had to comply with these guidelines. It sounds like the guy wants to sell new parts and not be bothered with setting up the machine, keeping it in good operating condition, and maybe having somebody who know how to run it properly.

The biggest issue with a brake lathe is sweeping up the iron particles afterwards.

Aardwolf

You could try garnet paper on the rotors.

Da Mail Man

nah....i don't think that was his intent since i heard this from more than one business. ford was manufacturing asbestos brake pads and installing them up to 1993 to correct some sort of a problem. i am sure that there may still be some pads out there that have asbestos in them. also, like i said before, the rotors can have imbedded asbestos in them....

thebeerman

Mail Man, I can't see where you are from, but I have never heard of the epa getting involved in machine shop grinding of rotors. In fact, in Colorado every Pep Boys, Checker, Napa, Target, etc. etc. turns rotors and drums.

If your rotors are glazed, no doubt so are the pads. Throw the old pads away, get the rotors turned, then be careful testing them out - you could become a hood ornament! It sounds like you have checked everything else.

Da Mail Man

i am in orlando, florida. really, i don't make this stuff up!...i can give you the names and phone numbers of the businesses (auto zone, advance auto parts, central auto parts) if ya wish.... i was told that as you have read previously. when i get the time i will contact epa in writing and get the explanation and further verification.


moving on....the rotors are really the only thing left. i am leaning towards a glazing of both the pads and the rotors but, i never thought it could be this bad and make my braking almost non-existent!

thebeerman

I live in the Denver area, and work in the mountains. It is very common around here (glazed pads and rotors) because people use their brakes a lot to slow down without coming to a stop. Unfortunately, the better the brake pad (longer lasting) the more prone to glazing because they use different compounds that last longer but glaze faster. Sometimes just doing a couple of hard braking passes, coming to a full stop, will burn the glaze off, but it sounds like your are pretty well gone. When you hear the glazed pads, it sounds like you are gouging the rotors and you will think the pads are shot, but when you pull the wheel you find there is nothing wrong with them. Since it is such an easy job to do brakes on the vette, and pads are readily available and cheap, you might even consider using the softer pads.

JAKE

I drove my car onto a grassy area one night and checked the performance of my ABS by jamming on the brakes while driving on the grass. At speeds as low as 10 MPH the ABS kicked in.

Jake

Da Mail Man

thanks for the reply...i have your everyday stock replacement pads all the way around. i hear no sounds from the wheels/pads while braking or otherwise except when they are wet after washing the car. then, when i slowly start (less then 3 mph) moving and apply the brakes, it sounds like a deep groan while stopping.

it was raining here a bit today so, i will test the brakes tomorrow.

i "broke the glaze" on the pads and rotors as directed by a machine shop as a test. i did notice that the back rotors had what appeared to be "pad material' imbeded into the rotors that was almost impossible to "remove". granted, what i did is only a test at this point. i will let ya know!

JAKE

I know you already checked the booster, but make SURE it isn't cracked. I had a similar braking problem and it turned out to be that my plastic booster was cracked on the engine side in a location I couldn't see until I took the booster off.

Seems that exhaust heat, especially when headers are installed, cause the plastic booster to crack. I even read about that happening in one of the Vette mags (as luck would have it I read this AFTER I solved my braking problem) and they fashioned a heat shield to go on the booster between the engine and the booster.

Just my thoughts.

Jake

Da Mail Man

thanks for the reply........yes, i thoroughly inspected the booster and applied an external source of vacuum to it and it appears to be good.

i have 2 extra spare boosters in the garage which are good, so i "plugged those into the engine" and the idle and the engines "reaction" to those are identical. i have rulled the booster out as a possibility.

JAKE

Any chance the vacuum connection at the plenum/booster is leaking?

How much pedal travel do you have? I had to shim the booster to M/C rod to take up the slack in my pedal after changing boosters.

BTW, when my ABS died last year, my brakes continued to function normally, just as GM says they would. I just didn't have ABS functionality.

Jake

Da Mail Man

thanks for the reply....NO CHANCE that the booster or the hose or the valve is defective or leaking as i have previously covered this. the pedal travel is fine as i have covered that too in my previous post(s). no adjustment(s) were needed and pedal travel is NORMAL. my abs is and appears to be working it's just that i have lousy brakes and they are just plain BAD! i have gone through the entire system and the only thing left was what i did today and hopefully will test tomorrow.