Brakes

[Nino Mastrocola]

My 93 1g awd has the AEM 12.5" front rotors with stock 2 pot calipers, Carbotech Panther pads all around, st.stl lines, new rebuilt front calipers and master cylinder and it has ABS. There seems to be this thing that I have to double pump the brake to get a firm pedal. Others have experience the same mushy pedal while racing. Many supsect the ABS system and bleeding procedures with the ABS. Any comments please...

[ohmygawd]

I'm waiting to see a reply too. I just purchased the AEM big brake kit front and rear, with SS brake lines. Haven't installed them yet, though. I'm waiting on the Brake caliper lacquer to come in.

When I first bought my car I had a similar double pump problem. My pads were very worn almost down to bare metal. After changing them I didn't have to double pump to have a firm pedal.

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95GSX
http://www.zing.com/picture/p96d08345b4b3a1eb71cffca209ea66a2/ff734d4a.jpg.orig.jpg

[Genius]

According to the shop manual, the brake bleeding procedure for ABS equipped cars needs to be done with the engine running. Maybe that's it. ;)

[joec]

How are your REAR brakes? Do they slide freely on the caliper slides? It's pretty common for them to rust and stick (bad design). When mine were stuck I'd need the double pump to get a firm brake pedal. Fixed it by taking off the caliper (and bracket) and freeing up the slide and wirebrushing all the rust off it.

I think what happens is that one of the slides rusts up (the one with the little metal cap over it). When you apply the brakes, only one side slides so the pad gets cocked sideways. The first pedal pump cocks the pad sideways, then the next pump feels firmer because the pad (well,half of it) is then closer to the rotor. Once you start moving again, the pad again moves farther away from the rotor.

WARNING: you can order a loaded replacement caliper, but make sure you get the ones that's specific to the 1G w/ ABS -- I think it's a 1322 casting. The ABS mounting bracket is different, the parking brake cable mounts from the top instead of the bottom -- learned that the hard way.

Check to see that the REAR calipers slides freely, also, if the rear brake pads are warn unevenly the slides are probably stuck.

[Rdy2race]

Also what order did you blead them in if in the wrong order you will never get the air out of the system start on the pass rear then the D rear to the Pass front to the D front

this is the correct order

[joec]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Rdy2race:
Also what order did you blead them in if in the wrong order you will never get the air out of the system start on the pass rear then the D rear to the Pass front to the D front

this is the correct order <HR></BLOCKQUOTE>

Bill, isn't this different than the order in the factory manuals? I seem to remember the Mitsu manual ('92) saying to do them diagonally (sp?) -- Passenger Rear, Driver Front, Driver Rear, Passenger Front.

I know the general rule is to start from the farthest caliper (from the master cylinder) and work your way to the closest. I just figured the Mitsu spec was because the brakes are linked diagonally (opposite side front/rear linked together).

[jags95gs]

joec is right i do believe. the 95 manual says pass. rear, driver front, driver rear, pass. front. i think 1g and 2g are the same

[Nino Mastrocola]

Yes, I have to check the rears. the rear calipers are very subject to building up a lot of sludge & corrosion in the actuating mechanism inside the rear pistons, which will render them useless, i.e. the piston will no
longer adjust or take up the slack between it & the pads, resulting in a low pedal that pumps up, just like you described. There is an easy way to check basic actuator function, or adjustment. Just depress the brake pedal, & set the parking brake. Now release the pedal, depress the pedal again, & while holding your foot on the pedal release the
parking brake. Did the pedal drop when you released the parking brake???
If so, the rear calipers are not staying adjusted, & should be replaced. Also, it is critical for rear caliper operation that the parking brake be used properly every time the vehicle is parked, so that they will remain
functional & stay adjusted. To use the parking brake properly, you MUST
depress & hold the brake pedal before releasing the parking brake, this
serves to lock the adjustment in, so to speak. I may be getting rebuilt rear calipers.

[joec]

Nino,
The part I'm talking about is not the piston retraction -- it's the actual caliper slides (lock pin and guide pin). The one that does NOT have the exposed bolt (I think that would be the guide pin) often rusts up and seizes. If the piston retraction wasn't working well, the brakes would drag (do they get really hot in normal driving?) and that shouldn't cause you to have to pump up the brakes since the pad is already right against the rotor.

Another possible problem might be due to warped rotors. The rotation of a warped rotor will push the caliper piston further into the caliper. This means the piston has to travel farther to reach the rotor and might cause your brake pump problem...

[thrownrods]

did you guys have to do any modyfiing to get the AEM big brake kit to work on a 93 awd? from wut ive seen they dont sell for that year. thx

[Nino Mastrocola]

Yes, there are 2 issues when putting AEM 12.5" AWD brake kit on a 1G. First, if you have ABS brakes, you will have to drill 2 holes in the aluminum hat of the AEM rotor to clear over the 2 bolt heads on the hub which hold the ABS sensor ring. 2nd the lower control arm rubs on the rotors so you have to bash in the edge of the lower control arm end, just under the ball joint, and grind it down as well. You have to do it about 180 degrees around the end of the arm. It may still rub during very hard cornering as the bushings flex. Thats it.

[Frisco]

I'm interested in the AEM 12.5 kit...who sells em and how much are they running?

frisco