belsy

My 90 has soft pedal, are the master cyls. the same as C 4s and are there better ones out there or newer years improved??
What is best bleeding process (I have a helper to do it the old way) I have never used a power bleeder is it worth it? Also are there rotor upgrades and/or drilling options?

Thanks for any opinions and info!!
Gene

kalister1

I bought a power bleeder that used a universal cap, it fit on with chains and 2 J bolts. I did not like it, did not use it, I did not get a good seal. I used my old Mity-Vac pump to suction bleed mine. Most folks here use Speed Bleeders, special bleeder screws that are spring loaded with a check ball.

bldavis11

Are the brake lines still the factory rubber or have they been upgraded to stainless? The factory ones have been known to "balloon" as they age. Just a thought, and a real easy thing to check!

thethrillofspeed

The brakes on my ZR1 are soft as well, I have not looked into it yet, but wanted to see if anyone had any good ideas. Kinda interesting how the 100% original little brakes on my 85 feel better, so something has got to be wrong.

bldavis11

There can always be air in the lines. I would recon a good percentage of "soft" brakes can be firmed up by a good bleed job.

Barbara_S

Same here on the ZR1 brakes - I just put race pads on and flushed the brake fluid. I went to bed the new pads this AM and found the pedal much softer/less responsive than my 88 brakes. I happened to look at the brake lines tonight while on a lift - and they are fine. I was surprised but glad to read this isn't unique to my ZR1.

bldavis11

Are they fine when someone's pressing on the brake pedal?

Barbara_S

They do stop the car but they don't have the same feel as my other car where I just touch the brake pedal and it abruptly starts stopping the car. I based my comment on trying to bed race pads on the highway - I just expected the same pads with a similar C4 to feel the same in braking and although I haven't bedded pads in 2 years the pedal was soft, reminded me more of a 70 Ford Fairlane feel than what my 88 does.
For the last few months I haven't really focused any attention on the brakes because the car has had lot's of other things to fix. I'll re-examine this in 2 weeks, after the suspension is changed.

bldavis11

So the pads are bedded or no? The Z is also heavier than a stock '88, so that will have a little to do with the different feel. I don't think that it should be like a Fairlane though! We'll get it sorted out. No great shakes.

Keep us posted on the suspension mods as well as how the track goes.

YorkL8apex

My pedal got soft at about 30kmiles. I have ss lines and bleed my brakes about once every two months unless AXing a bunch or doing a track day.

Replaced my Master Cylinder and it was better than Viagra, pedal now hard for hours at a time

Used NAPA parts no problem.

If a good bleed does not bring the pedal back, try ss lines first, then go for the MC

bldavis11

100%. That's the order! How bad was the master cylinder job?

tomtom72

Changing the M/C is easier than doing the plugs. Two 13 mm nuts on the booster, one electrical plug for the warning light, the front hard line 11 mm(?) flare wrench and the rear 14 mm flare wrench, the vac line to the MAP under the ECM gose between the reserviors, and the in-board nut on the booster has two brackets for hoses. Piece o' cake. Don't forget to bench bleed the new one before installing it.

Discon the brake switch plug and vac line to the MAP first. Then brake loose the hard lines from the front & rear reserviors. Then hit the two 13 mm nuts on the booster studs, then remove the hard lines completely. There is plenty of slack as the hard lines join to two s/s braided lines. The two hard lines are just two short "U" bends that meet up with the s/s braided lines under the M/C.

To bench bleed use a caliper bleeder on the front port and a bleeder from a slave cylinder on the rear port with some vac hose into the reserviors. Don't forget to be gentle at first as the new one is dry. I usually fill and wait for some fluid to come out of the ports before I start pumping the M/C piston. Slow pumps do it and be careful not to go too far with the piston travel. Once the front reservior bleeds out the rear one will start to bleed out.


Tom

YorkL8apex

RoadRace65 did my MC install but with the post above. One of the few things that are actually pretty accessible in ZR-1

belsy

Wondered if the later single res m/c is better and can it be put on a 90???
If so is it worth it??

Jeffvette

Yes it can.

But, the only bad thing about it, is when it gets dirty, you can not wipe out the forward most part of the cannister to remove grime. The early style two resevoir system is better IMHO.

I run a modified Camaro master in my car.

Zethco

My first thought was brake lines - Even low mile cars can get soft-pedal syndrome. The old lines expand like a *****.

My TTA had the same problem. I put SS lines on my TTA (and my Z later). Now, if I even THINK stop I'm headin thru the windshield

I'm sure you're well aware of the upside of SS brake lines. Even if that's NOT your issue, absolutely start there.

The best 100 or so clams you'll ever spend. Period.