Got the rebuilt master cylinders...

ubercrap · Post by **ubercrap** » Thu Jul 15, 2004 8:54 am

...from autopartsgiant.com last week, just forgot to post. They look to be correct to me. Of course it's difficult to tell until I actually try to bolt one in, but they have the two mounting "ears" sticking off of them that look right. I'll take some pics maybe to see what you guys think.

raygreenwood · Post by **raygreenwood** » Fri Jul 16, 2004 12:03 am

Just to be sure....and you should do this with any cylinder anyway (it used to be in many tech manuals) ...diassemble it carefully and wash off the assembly lube crap. Its fine if its Bosch or Lucas brake paste...but its doubtful that it is. Its usually a coal oil derivitive. It also tend to gum up proportioning valves. But...while you have it apart....check the piston lengths inside to the original cylinder you have, Make sure they are the same. I have found more than one rebuilding house that stupidly slapped in "similar" pistons for rebuilds. They must be precisely what came out. this goes for any master cylinder. If the pistons are more than .5-1.0mm off in length or position, they will not replenish from the metering ports in the fluid feed above. This is also why your brakes will suck...if the stroke length of the pedal is set wrong and does not allow the piston stack to fully come back to start position when you let your foot off. The type 4 pistons were unique in chamber volume and stop pin length. You canot swap pistons in from anything else.

Also...if they do have correct pistons, chances are they are used originals. Many rebuild houses simply hone the cylinder...which is incorrect...and snap new seals and flap valves onto the old pistons. Thats OK...if.....they carfully honed the flap valve surfaces on the pistons clean. If there is any manner of pitting or corrosion on them...and many times there is.....the pistons will not work. Also, some houses chrome or zinc plate the pistons to get areas like the flap valve surfaces smooth. That can leave residue plugging the holes.

If the cylinder has hone marks...get some 1000-2000 grit sandpaper....roll it around a dowel....and lap the cylinder smooth. Inspect for subsurface rust pitting. Many houses again...simply hone everything and do not inspect. Any rust pits...and the cylider will perform poorly...if at all.

ubercrap · Post by **ubercrap** » Fri Jul 16, 2004 6:08 am

OK, I'll take one apart at some point and inspect it and try to give you guys a report.

67 T1 · Post by **67 T1** » Fri Jul 16, 2004 6:58 am

Uber
Have an extra hood, "cheap cheap, 5 dolla"
http://www.thesamba.com/vw/forum/album_ ... ?cat_id=31

edit: posted under panzerace 88, 412 hood

ubercrap · Post by **ubercrap** » Fri Jul 16, 2004 7:07 am

Hey, it doesn't look too bad, and you can't beat the price!

I'll be down there to pick up my other 2 412's at some point here, just don't have a concrete date set at the moment. It's a little farther north of where you are, but maybe I'll take some vacation time so I don't have to kill myself to get there and back in a weekend and I'll swing down there.

67 T1 · Post by **67 T1** » Fri Jul 16, 2004 7:34 am

have rickshaw, will travel.