Brake Question--Not about upgrade

[timhodge]

Well, I guess it kind of is, but not really.
I upgraded my 89 with 95 disk parts. Went pretty well. Used 93 cobra booster with the 95 master cyl.
Got everything bled and the pedal is hard as a rock, after starting engine, I get about 2 extra inches of travel in the pedal and no amount of bleeding, including re-bleeding the mc, seems to get rid of it. The pushrod is set to spec. I can't find any leaks, so I don't know what to try next. I'm thinking the mc maybe has a weak seal that only shows up under the increased pressure with the booster activated. If there are no other ideas I will try changing the mc next but I would really appreciate any help/ideas. Thanks in advance. Tim

 

[timhodge]

Well, I worked on it a little more this weekend. I plugged the line to the front at the mc and the pedal firmed right up. Plugged the line to the rear and mushy again so I checked the caliper pistons for excess movement and they are moving in about 1/8 to 3/16 inch each pedal push. Then moving back out the same amount when released instead of staying up against the rotor. I think this is too much but not sure why it's doing it. This is with the car up on jacks and no wheel movement. Right now I'm thinking I'll drive it a little and see if they will seat up a little better with some wear. Otherwise I guess just try some new rotors and calipers. The pads are new.
Any other thoughts or ideas welcome, as always.

 

[Blandnuts]

Did you bench bleed the mc? What did you set the pushrod to? What was your method of bleeding the brakes? Not trying to be an ass, just trying to get a base on what was done.


Fred

 

[timhodge]

Did you bench bleed the mc? What did you set the pushrod to? What was your method of bleeding the brakes? Not trying to be an ass, just trying to get a base on what was done.


Fred

Did you bench bleed the mc? yes

What did you set the pushrod to? around 31/32

What was your method of bleeding the brakes? Plain old 2 man method, with an assist by tapping the calipers with a rubber mallot. Have heard the 95 calipers tend to hide some air, and this helps to dislodge it.

Not trying to be an ass, just trying to get a base on what was done. Not a problem. Thanks for the interest.

Tim

 

[Blandnuts]

That's odd it got better when you closed off the front brakes. Are the brakes consistent when driving? How's the stopping power? What proportioning valve did you use, and how did you set it to bleed the brakes?


Maybe I'll eventually stop asking questions



Fred

 

[timhodge]

That's odd it got better when you closed off the front brakes. Are the brakes consistent when driving? How's the stopping power? What proportioning valve did you use, and how did you set it to bleed the brakes?


Maybe I'll eventually stop asking questions



Fred

Haven't driven it much at all. Drove about a mile and tried some panic stops. The brakes work, but couldn't lock up the wheels. No pulling, strange noises or anything else unusual though. I'm still considering putting a few more miles on it, and see if the pads seat in better.
Used the FMS prop. valve set at max rear brake, can't remember if that's all the way in , or out, but you know what I mean.
Ask away, I'm not going anywhere.
Tim

 

[Blandnuts]

Yeah, put a few miles on it. Here's a site to help bed-in your brakes. It seems like you did all the work right and after proper bedding of the brakes you should have better stopping power. I'm still not fond that the pedal goes almost to the floor.... Anyways, post back up if you find anything.


Fred

 

[Blandnuts]

Instructions for bedding in your brakes