Spongee brakes...

[Tailites]

OK...no newb to this stuff...but no matter what I do I cant get the figgin air out of my brakes

tried all the appropriate methods...pressure...suction...

its good but not great...it stops fine...just cant get it hard (insert vulgar comment here)

thought it might be the master...tilted the car...all the tricks

nothing seems to work...its a Fox body 91

the master has three lines...tanx

[ZR]

What set up are you running?

[Tailites]

What set up are you running?

I swapped out the rear drums...it has rotors now

the master is a new reman...all stock/stockish stuff

the rear calipers have rubber flex lines

[ZR]

Need to know exactly what you used for

-calipers
-master
-prop valve
-etc

[Tailites]

Need to know exactly what you used for

-calipers
-master
-prop valve
-etc

calipers would be the super coupe...but Im not sure on this
stock master
no prop valve...it actually stops very good...no lock up at all
the etc part...hm

[ZR]

So your using the stock disc / drum master?

[tulowd]

couple of things:

could be wrong master which means replacing with correct volume and piston size
need a adj prop valve to set the brakes up correctly
if there is air in there, you need to gravity bleed them first, and also tap the calipers with a deadblow hammer - sometimes air bubbles attach to the inside of the caliper and wont come out.

[Ponyryd]

Why no prop valve?

[Tailites]

So your using the stock disc / drum master?

yep

[Tailites]

Why no prop valve?

several guys did the conversion with no prop valve & it worked fine

[Tailites]

I will figure it out...I always figure stuff out...

with your help of course...:thx:

[ZR]

I've had several in with discy conversions that "felt fine".
Does need the correct master
Suggest prop valve delete with external / adjustable valve.
Stuff from Maximum Motorsports is priced very affordable and comes as a bolt on kit (lines etc come made up) and looks more stock vs stock.

[tulowd]

several guys did the conversion with no prop valve & it worked fine

act of god. For the sake of a few dollars and some fittings, it's unsafe and stupid not to put one in.

Have any of these guys tested the brakes for rear lock up under various conditions? Having your rears lock first is not fun when you really need to stop and or avoid obstacles. By the same token - if not enough pressure goes back there, the rears aren't doing their full job, which is to help the fronts decelerate the car at the highest possible rate. A balanced braking system is awesome and makes any car safer.

[Tailites]

did the set up work initially and deteriorate to this state or is this a new install/conversion?

no...its always been a bit spongee...theres air somewhere

[ZR]

-calipers on at the correct angle to properly bleed?
-parking brake hooked up?

[svo1990mustang]

New calipers? Are they on the correct side?

[Tailites]

-calipers on at the correct angle to properly bleed?
-parking brake hooked up?

yup

[Tailites]

New calipers? Are they on the correct side?

yup...bleeders at top

[Tailites]

act of god. For the sake of a few dollars and some fittings, it's unsafe and stupid not to put one in.

well I guess the Lord knows Im stupid & cut me some slack cuz the car stops fine...

have you honestly tried a conversion with no prop valve?...

then you really dont know...

what I do know is it works...come & drive the car & tell me otherwise

my car is turbo...you think Im going to be goofy with brakes?...hardly

[tulowd]

oh ok; because you haven't installed it and it seems to work, it must be fine? The factory knows the weight bias and performance of the car, so they can design a non adjustable diverter.

For the amount of effort dough and knowledge you put into your car this is disappointing.

Oh, and you have spongy brakes, but they work fine? If you are not getting enough pressure in the system you are not maxing out braking performance.

Research and see which master cyl you need for this. When I installed T bird rear discs on my 84, I had to use a MC from a full size like an LTD I believe.

[toofast306]

Research and see which master cyl you need for this.
Word.
My conversion included an SN95 MC - bigger piston for more fluid to the calipers.
I think I still have a spare MC from a 4 wheel disc car... and a matching prop valve... and FMS spark plug wires...

[b1lk1]

Wilwood sells an awesome adjustable proportioning valve that takes the place of the stock prop valve completely. I put one in my van because the prop valve failed in it and trying to find parts for a 1992 Dodge van is insanely difficult. I will be using the same valve when I put rear disks in my Mustang.

http://www.wilwood.com/Images/MasterCylinders/MasterCylinder_Photos-Large/260-11179-lg.jpg

It even mounted to the stock bracket without issue.

[onDjuice]

^^ used that many times works great.. But Glen is as Rocky said a ham and egger.

[ZR]

Yes SN 95 master n prop valve works mint on them as well.

[Tailites]

^^ used that many times works great.. But Glen is as Rocky said a ham and egger.

nice one Tony...why dont you come over & fix my brakes

I promise to stay out of yer way...

well a slam back a pint or two...ha ha!...Ill supervise

[Ponyryd]

Wilwood sells an awesome adjustable proportioning valve that takes the place of the stock prop valve completely. I put one in my van because the prop valve failed in it and trying to find parts for a 1992 Dodge van is insanely difficult. I will be using the same valve when I put rear disks in my Mustang.

http://www.wilwood.com/Images/MasterCylinders/MasterCylinder_Photos-Large/260-11179-lg.jpg

It even mounted to the stock bracket without issue.

Agreed, this is ideal IMO because you can set it yourself. No prop valve is a bad idea.

[onDjuice]

nice one Tony...why dont you come over & fix my brakes

I promise to stay out of yer way...

well a slam back a pint or two...ha ha!...Ill supervise

I knew you would like that. No problem with the help just super busy building trannys. and trying to find that iac adjuster for you..

[jibbijib]

Have you tried removing the sponge from the master cylinder?

[Tailites]

Have you tried removing the sponge from the master cylinder?

whoah!...never checked it!

thats the sponge that builds up over time...right?

[jibbijib]

Ya, you gotta squeeze a few drops of turtle wax in there to get it loose.

[b1lk1]

Should work fine, if it were me I'd have the tee for the front centered between the front brakes somewhere.

[ZR]

MM makes a kit to remove, slick as hell and costs very little.

[tulowd]

I had a thought today as I'm going to redo the brake lines in Cunnifer on my 93. Since I'm using a manual prop valve for the rear of the car, can I remove the factory prop valve completely. Seems to me I should be able to come out of the master with the port for the fronts going to a tee and then to each front caliper. The port for the rears passing through my manual adjuster and then teeing at the back somewhere to the rear calipers.

Am I missing something?


You are correct. Here is how I did mine; one tee below out of view for the RF and rear lines to cross thru the K member, cleaning up the firewall at the same time.

http://i1245.photobucket.com/albums/gg582/tulowd/87%20Vert%20TU%20LOWD2/MCinstalled1.jpg