The Stovebolt Site Forums The Parking Lot Tons 'o Fun master cylinder issues

hi guys,
i have a 56/57 grumman stepvan on a chevy frame/drive train
apparently i shoved the plunger through the piston and now the pedal just floats freely....

i have had little luck finding one to replace it with, closest i have come is a rebuild kit out of argentina on ebay.

does anyone know of a good source for replacements?
thanks,
bruce

"apparently"? maybe you should find out for sure what's wrong, it'd be pretty hard to "shove the plunger through the piston" - you don't want to be looking for a Grumman part, the MC should be factory GM for the chassis, and depending on the chassis model [3/4T?] a MC or kit may be available locally ..... from your picture it looks like the standard 55-59 light truck MC

Bill

first few seconds shows the brake pedal just floating.....

apparently i more possibly shoved the plunger deep down a corroded dry cylinder
i know all about step van parts and their respective frames/drive trains, this is my third one....second one rebuilding, and first with a frame mount MC

this is also the oldest one i have tackled, and after 56 years there is little to nothing left in the form of ID plates and the such...
i have a VIN, ps327b126005 but have had a tuff time trying to decipher it, i know baltimore and thats about it

and apparently the "s" was sometimes included on service vins

The step van parts are listed as P series in the catalogs. Back then they were usually referred to as Duble-Duty. A good parts man should be able to find a rebuild kit or new master cyl.

problem is, the way it mounts is with 3 bolts, on a flange sort of like a normal master cylinder would attach, 2 bolts either side on top an 1 centered on the bottom.....
most everything i have found is a through the side between the cylinder and reservoir type mounting holes.....

the closest thing so far to being a visual match(that is actually available in my world) is a late 50's corvette style MC, and at around 400 bucks is out of question....

the rebuild kits i found from Argentina look like pretty decent kits and at 18 bucks are a viable gamble....

i know there has to be a source somewhere....everything i have found that looks like a match are out of stock/unavailable/blah blah blah

i just found found a match on ebay out of Michigan for 55 bucks, lol, cross those fingers!

i still am not 100% sure what i have frame wise.... what are good things to put together to piece a picture of what im dealing with?
ie: brakes/e-brake/springs/etc....

thanks for the help guys, this isnt my first rodeo, but i sure am learning i dont know as much as i thought i did with this one, lol

oohhh one more question....

on the rebuild kits, are they, say...10 thousandths over to allow for honing?, stock size unless otherwise noted? do they come in different sizes like pistons do ?

thanks

main thing im wondering is do they come oversized as a rule or do i need to find that info out before sending money....

ok,
pics looked at, questions answered, part ordered...

http://www.ebay.com/itm/121337786521?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

gonna start blowing out lines and inspecting wheel cylinders this weekend...... didnt take too much to track one down, just had to be a little patient

out with the old..... im sure i will need to swap in my old plunger, and possibly the end fitting the banjo bolt screws in to..

http://i762.photobucket.com/albums/xx267/93MARKIII/57%20step%20van/securedownload_zpsdbbdb4b0.jpg

http://i762.photobucket.com/albums/xx267/93MARKIII/57%20step%20van/plungerrod_zps10e9fd10.jpg

ok,
part came in today, i swapped out the plunger rod and installed!
i need to bleed everything of course, but i have pedal pressure...

i slowly pumped the pedal until the air bubbles slacked off, and then gave some good leg pumps and the pedal stiffened right up, but she still needs a good bleeding but that have to wait till i get some help

I bleed my brakes by myself. I use a clear hose from the bleeder to the jar and it works just fine.

yea, im gonna give that a shot, gonna pick up one of those bleeder kits tomorrow

i dont know how stock you wanna keep your truck but if i come up with enough $$,i can retrofit 2 pot mc and dual diaphram booster for under $200.,off e-bay.if im gonna haul 3 cords of firewood 40 miles at about 60(to keep from gettin run over, most do 70mph here)im gonna be able to stop.ive had incedents that would make most men have to change there shorts.mostly connected to poor or no brakes. gl to all on your projects

Looks like the same Master Cylinder as I have on my 1960 P-20.

I think I just got my Kit from the local "NAPA" Parts house.


But I noticed what you are saying also - most Chevrolet Trucks of that time period has a different Casting and Mounting for the Master Cylinder than like what you have ( and I have ).

Get yourself a heftier return Spring while you are at it, too.

Your Pedal return is a mite languid...and should be a little more definite and strong.

I Flushed and Bled my whole Brake System the other day using a couple feet worth of clear Plastic Tubing, running it into a Bottle.

Tubing slips over the end of the Bleed Fitting...crack the Bleed fitting a tiny bit, get in and Pump the Brakes, MC 'open' so you can watch, re-filling it as need be...then, once you figure the line to THAT Wheel has had enough new Fluid to run all the way through, close the Bleed Fitting and go on to the next Wheel.

I totally re-did my entire Brake system five or six years back...new Wheel Cylinders all round, I think I got an NOS Master Cylinder, and new Flex Lines also of course.

None of these cost all that much, and if memory serve all these parts had a long application run, so, they are still easy to get.

You can get your Master Cylinder and wheel Cylinders 'Sleeved' in Stainless Steel or Brass...uhhhhh...I used to know the place which did this, and now I can mot remember their name.

They have a good reputation though and do very good work...you just send them your parts, they Sleeve them, and Hone them and send them back to you...you are good to go then with standard inards, since the Bores are all Factory Spec.

If their name pops into my poor sodden Heat dizzied head, I will post the info.

Are you thinking about these folks?
Brake resleeve
Harold

It was someone else.

No doubt, there are various places offering the Service though.

Initially I was thinking to have this done, then, I found brand new or NOS MC and Wheel Cylinders, and they actually cost quite a bit less, so, I never did try the sleeving, but, it looks good, and would be excellent I think for any really hard to find Master Cylinders and or Wheel Cylinders which need to be renewed.

I think it was "White Post" I originally looked into.

http://www.whitepost.com/brakeform.html