Found another Master cyl. for 4 wheel discs.

[broncoman6524]

In comparison to Muddybuddys thread on the Perfect MS, I found that an 85 chevy 3500 2wd had rear discs as an option. I bought a master cylinder from the truck.

Instant difference from my stock MS, the pedal is hard as a rock. Starts to slow at the VERY top of the pedal. I was thougholy SP? impressed.

On the dry road it's actually hard to lock up any tires, but when the do a quick let off and hammer it again and it's gone.

In dirt the rears still lock up before the fronts, as well as in rain. I'm going to blame the proportioning valve though.

This is on a 77k20 with a D44/14B using Stock K20 D44 brakes all around.

Best part is it's a METAL MS, no newer plastic resevoir.

 

[wasted wages]

Now all we need is the Mfg and the part #....

 

[broncoman6524]

Nice sarcasm. :P

I bought autozone, so it's a FENCO brand. New part number-NM1982 Reman- M1982

 

[wasted wages]

Now,,,you da man.....

 

[tacoma]

so there is a factory D70 or 14bolt disc option out there????? on '85's????

 

[dyeager535]

Autozone lists rear brake calipers, but Napa doesn't. From the picture, there is no e-brake provisions, which means it would have been driveline brake.

I suspect they confused the P series truck with the C. GM parts manual doesn't list C/K rear disks from '85-88.

 

[dremu]

Betcha betcha betcha that's the P3500 master that Camsk5 was using.

Fenco M1982

Brake Master Cylinder Bore Size : 1.31250
Brake Master Cylinder Line Thread Size : 1/2-20;9/16-18

1985 P30 disc/disc... seems to be the same for vacuum or hydroboost.

Safety Stop 39309 aka United UP 39309 (and aka Raybestos MC39309, IIRC)

Brake Master Cylinder Bore Size : 34 mm (1.3858")
Brake Master Cylinder Line Thread Size : (1) 1/2" - 20 & (1) 9/16 - 18

Huh. Aha, same family, just different bore. Lots of info from the GMC motor home people:

http://users.california.com/~eagle/master cyl.html

-- A

 

[87 Blue Beast]

Nice sarcasm. :P

I bought autozone, so it's a FENCO brand. New part number-NM1982 Reman- M1982

so did you buy the new or reman one and how much was it?

 

[BGKYK5]

Keep the info coming, good stuff!

 

[MTBLAZER89]

Yeah I may just have to try this.

 

[broncoman6524]

I bought a reman, and it works fine for me. $22.99 plus $20 core.

 

[87 Blue Beast]

sounds like a real good deal. i too am going to be in that boat real soon. could you get a pic of it?

 

[djohnsn]

Has anyone tried a master cylinder from a late 70's Trans Am with 4-wheel discs? The bore size is the same as the K5. My somewhat local NAPA has one, so I know that they are still as least somewhat available.

 

[GM Man]

I'm guessing with the newer ms there is a metric change over for fittings, do you guys have any issues with getting those to work on older trucks?

 

[muddybuddy]

the p30 MC didnt work on my '88 k5 cuz it hit the booster before i could get it all bolted on.

seems like a possible solution. but ur running 44/14 right? thats a big difference from 60/14, the front calipers are gigantic

 

[broncoman6524]

Yes, I have a 44/14 with 44 calipers all around.

I've now driven it in the rain, the rears still lock up before the fronts, so I'm goin to look into an aftermarket adjustable proportioning valve.