Brakes!!!!!!

[L8RH8R]

I will try to answer all questions.

This is the kit I bought: http://www.ebay.com/itm/GM-Rear-Dis...Parts_Accessories&hash=item29fe946a4e&vxp=mtr

Before doing this swap, months earlier I replaced the old master cylinder with a "Firm Feel" master from SSBC at $200. The brakes worked fine for weeks up until this week. This time I replaced the master with a unit from a 2000 or 2001 Tahoe (can't remember what year we figured out at Autozone) that was for a dual disc set up. After bench bleeding the master and then the brakes, the problem remains. The rear calipers bleed fine once the pedal is pressed several times, there is just no pressure getting them on initial press.

As far as the prop valve, it's attached to the outside of the ABS unit. Is there a way to adjust this? Can I take one from a newer ABS unit and install it. If I go the route of the Hyroboost won't I be in a since going around the ABS all together?

Something else to note, the old Firm Feel master had a bore of 1.25 and the new one is 1.33. I would think this would be more than adequate to move fluid.

This is driving me nuts. Again thanks for the input.

 

[retorq]

No pressure on the first press would indicate you need a pressure valve.

Something like this: http://www.speedwaymotors.com/Wilwood-260-1874-Blue-Disc-Brake-Residual-Valve-2-PSI,1377.html

 

[SunlitComet]

wow $535. even the cheapest kit in catalogs is about $900-1000 and that is summit racing brand. they not only include a new mc but they instruct you to swap the lines. and remove the spring and seal of of one specific end of the valve. perhaps you can try their valve mod first starting at page 6 the of the linked PDF. http://static.summitracing.com/global/images/instructions/inst28 sum-bk1403.pdf

btw the ssbc mc you got was nothing but a nbs mc with a line bushing added really.

rear disc conversion are not a big power enhancement. you can do better in two different ways. a nbs mc would have have given you a firmer pedal while a hydroboost would have applied greater force with the same effort and would cut down on the "start to depress to brake reaction" time. add the rear disc on top of those to gives a tad more brake but much easier to keep clean, dries out faster, looks better over all and far less parts to act up or go wrong.

 

[L8RH8R]

Hmmmmm...very interesting that is. I'll remove that tomorrow and then bleed the system AGAIN (lol). I have to look a little closer at the prop valve on the ABS to see if it has the screw as in the photos. I believe it does. Again thanks for the input.

 

[SunlitComet]

pay attention to what side you remove.

 

[L8RH8R]

Removal of the spring, washer and complete bleed did not work. Problem persists.

 

[L8RH8R]

Bled the lines going into the ABS unit for craps and giggles to no avail. What if anything else could it be? Will a hydroboost unit not fix the problem.

Sunlit: On a side note, after reviewing the instruction sheet you sent (a great many thanks for that) I noticed the spring (in the prop valve) they have you remove is closest to the front brake line from the mc. I would have thought the spring closest to the rear brake line from the mc would have been the one to remove in an effort to increase pressure. ???

Again thanks for all the input.

 

[Monstar_est87]

I just noticed the Ebay seller u bought ur kit from... Hes a heck of a guy... Exchanged emails for a while he knows his stuff and can make all kinds of kits... Im sure sunlit or the ebay seller can help u figure this out... And hold off on the hydro boost till u get this problem fixed first...

 

[SunlitComet]

if mounted on abs they pulled one pointing up and away from center of vehicle.

 

[L8RH8R]

I did pull the right one (prop valve) after all. After looking at the one on the other end, it is completely different inside. I attempted another bleed today and discovered the rear calipers are barley moving. When the vehicle in placed in gear and the pedal depressed (to the floor), the rear wheels continue to rotate. There is absolutely NO pressured getting to the rears. Gonna try something else tomorrow. I plan on disconnecting the rear brake line from the mc, plug the port, press the pedal and see if i get a firm pedal. I'm dumbfounded.