danziger

OK. I've been out of the 3rdGen game since 1994, but recently bought a 1991 L98 Formula. The brakes seem terrible! I mean scary poor! Now granted, I have been spoiled by my recent stable of vehicles (Z06, C4, LS1 Z28, etc), but my wife's Buick LeSabre is more confidence-inspiring...
I have put on new pads and the rotors are nearly new. The only issue is that the brake fluid gets dark VERY quickly.
So, do the 3rdGen brakes suck (in which case I will upgrade to LS1s or similar), or do you think something is out of whack? Thanks!

//<86TA>\\

iTrader: (14)

in comparison with newer vehicles, the brakes do suck, but they should not be scary. You should be able to lock up the wheels with relative ease. If not, you probably have an issues with the booster, brakes, or a combo of a few things. If the fluid is that dark, you may want to flush the entire system, replace all the flex hoses and fill with new fluid and try again.

a upgrade of the front brakes would not be a bad idea. The rears should be 11" PBR's and are not that bad.

danziger

Well the brakes feel really spongy and don't seem to stop that well, making the Formy feel heavier than it is. I am not a brake guru by any stretch, so maybe I'll have them looked at since rotors/pads/fluid didn't do much (if anything). Thanks for the input! B

ebmiller88

iTrader: (7)

Did you flush the system and replace the hoses when you installed the newer parts? If not and you don't want to immediately upgrade, you need to. The issue is that the hoses will rot from the inside and restrict fluid flow. Second, if you're still getting old fluid out, you need to flush it until you get clear fluid out. You already have the good rear discs but they probably need some attention as well, such as lubing the guide pins and checking and replacing those hoses as well. There's a couple little things you need to fix first, then see what results you get.

Ed

vindeezl

iTrader: (2)

Good advice as always Ed, and YES they suck if you have the cast iron Delcos like me...

ebmiller88

iTrader: (7)

If you have those and cant' upgrade, rebuild them using the recall kit and you should be good to go.

Ed

danziger

ebmiller88: Yah, the front hoses/lines are new. The RF line was bad and pinching, so they got replaced. The fluid was bled until clear, but 1300 miles later it is black. Maybe there was an accumulation of crud in there?
Anyways, I'll probably man up and take it to a pro for an opinion...maybe I missed something.
I'll probably upgrade the fronts anyway to J55s or LS1s...the aftermarket stuff gets pricey fast!
Thanks for your help!

danziger

Ed- By the way, I have the flynbye website in My Favorites if/when upgrade time comes...

gmanuel

spongy feeling brakes would tell me that you still have air in your lines.

Stephen

iTrader: (12)

Cast irons don't automatically suck.

If I can lock up all 4 & leave 4 big black marks (trying to dodge a deer on the road) That would tell me...My small rear discs with iron calipers do a pretty good job.

Things like braided brake lines are 1 improvement you can make over the stock rubber lines. They won't swell under pedal pressure, during braking.

JamesC

iTrader: (5)

Though they have a bad rep here on the board, I agree with Stephen. I had them on my car for several years and thought they performed well enough.

JamesC

the blur

yeah, they do suck. even with the 1le's, and playing with prop valves for years, they just suck.

I went with a more agressive pad to "solve" the problem.
actually I found OEM C4 pads seemed to be a streetable pad that made the difference. the pad was made by PBR.

chevyracingrox

haha yea, deer have been a real problem this year. i get into a wooded area and start driving like an old granny. cast iron rear discs are still better than rear drum.

maybe your master cylinder isn't holding pressure anymore. mine was pretty bad. I replaced it and now I have to make a huge effort not to lock up my brakes, especially in this weather.

Toyota h8r

ive got a 4wheel disc car with aluminum rear calipers and its a pain in the rear not to go into all wheel lock up sometimes.......i love these brakes so far

Stephen

iTrader: (12)

If can lock all 4 tires, keep them locked & leave 4 black skid marks...I'd say my MC is holding pressure pretty good.

Toyota h8r

lol i was thinking same thing

i dont know why people knock f-body brakes. just have to upgrade the size of the rotors in the front and leave the rears alone. 11.6's in the rear are big enough for me.....least til i start road racing

ebmiller88

iTrader: (7)

You've got the good rear discs, that's why..it's the guys with the earlier '84-88 rear discs who usually have the issues. The '89-up rear discs are fine, same calipers used up until '98 and Baer still uses them in rear disc conversion kits. Good indeed.

Ed

Toyota h8r

OHHH! i gothcha

Stephen

iTrader: (12)

Then please explain my 87 "tiny discs? I certainly can't complain, when it has the ability to lock all 4 tires......Yes, larger should/could/would be better. But visually? Yes...They suck behind my 17" Snypers.

That alone makes me wanna upgrade to at least 4th gen or C5 disks. Just not sure what it would take to put those on my 9-bolt.

Toyota h8r

If i remember correctly, Ed makes the conversion brackets?

crytical point

other than the wieght the rear drums aren't so bad because I can lock all four up on my 92 RS with v8.

chevyracingrox

I wasn't refering to your brakes, i was suggesting what could be wrong w/ the original poster's brakes.

its not about the initial bite, rear drum have an advantage there. drum brakes lock up quicker than disc. the advantage of disc brakes is there ability to shed heat quickly.

danziger

Hmmm. Maybe I effed up, but I went corner-to-corner and thought I got all the air. I don't have fancy bleeding equipment, tho...maybe I'll take it to a professional. Weak brakes are
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I'm not sure if this is directed towards me, but thanks for the suggestion!

chevyracingrox

yea, its my suggestion. when master cylinders get old sometimes the seals on the piston won't hold much pressure so it just pushes fluid around in the master cylinder and doesn't create a ton of pressure. like when piston rings get bad in an engine and it starts burning off oil. exept in this case its not such an obvious problem. its just my suggestion, I could be wrong.

Flip 2

iTrader: (1)

83 OE 4 wheel discs..... not too good.....

91_5.7_TPI

iTrader: (2)

Being able to lock them up isn't really an appropriate indication of performance. That's just 'shocking' the tires enough to break traction. The reason for the superiority of the larger rotors/calipers is that the larger rotors shed heat faster as well as act as a longer 'arm'. When the caliper is further from the hub, the more leverage it has to stop the rotation. Also, larger calipers with more pistons offer larger surface area on the pads, allowing for more bite. The combination of these attributes means that the brakes can handle more heat cycles and still dissapate the heat and the brakes will go longer without over heating.

My recent LS1 front brake upgrade with OEM pads stops alot harder than stock from higher speeds. I can even induce rear brake hop from 75-80 and up- something I couldn't do before. But, the OEM pads (even with the larger front brakes) don't allow for the same hard-bite stopping from less than 10-15 mph as the Hawks HPS I had did. I'm thinking about putting the Hawks Ceramics on the front to match the new rear pads at some point.

That being said, for just street driving, new stock parts coupled with new fluid (with no air) and good performance pads can provide a decent stopping car. I ran the stock fronts with Hawks HPS and the 89+ disks with HPS for years and had plenty of hot runs on the mountains and some ~ one minute auto-x runs without issues.

danziger

Yah, I'm beginning to think that maybe there is a problem somewhere in the system as there is no way 4-wheel discs can feel this sloppy. I'm going to have it looked at and I'll post the findings. I still might go LS1 fronts...