Master Cylinder Overhault/Swap

denpo

denpo

Carburated Nihilist
Joined
Jul 14, 2010
Messages
2,523
Location
Montreal, QC
I've checked my Master Cylinder and the rear reservoir is full of rusty muddy crap. That's on par with the state of the brake line I had.

My option 1 is rebuilding it
I tried to tear it apart, but there is this snap ring.
Searched on the web, and all I found was "use a snap ring plyers" advices.
Thing is this ring has no holes, no notched, nothing, just a metal ring, and it looks kinda stuck in its groove.
I have a pair of cheap ring plyers, but I don't know how the hell I could use it to remove it. Is a special tools needed here? Any work-around?

My option 2 is modding
Last time I when to the scrapyard I saw ton of those slim aluminum MC with plastic reservoir. Maybe getting a newer MC would be a good idea. Is it?
Apart from the obvious physical differences like the bore size, is there something I should be careful about when finding a replacement MC?
 
I followed TT's advice and put a C5 master cylinder on my '69. They're dirt cheap, reliable, easy to install, look great, and 7 1/2 pounds lighter than the cast iron C3 master cylinder. The lines (metric to SAE) require a little work, but easy to do once you know how.

Just my suggestion.
 
Wish I had known of the C5 m/cyl mod working with HB...

back when...

I went with something with a oval cap and two screws holding it in place...
aluminum from Pirate Jack racing.....
stock diameter for a C3 on the pistons, and almost a direct hookup....

weight? dunno....hellofalotlighter....


:eek::gurney:
 
Use a small pick to remove the snap ring that you described.

C5 master cylinder has a 1 inch bore like what came with manual brake cars not a 1 1/8 inch bore that came on power brake cars.

Stock replacement M/C for your car is cheap, why not go that route?
 
Fuelie74 said:
Use a small pick to remove the snap ring that you described.

C5 master cylinder has a 1 inch bore like what came with manual brake cars not a 1 1/8 inch bore that came on power brake cars.

Stock replacement M/C for your car is cheap, why not go that route?
Click to expand...
That's what I tried, I'll try again with a sharper pick et maybe so more force.
If I would go stock replacement I would first check if the one I have is remanufacturable, because, Well, cheap is a relative measure.

Buying a new front clip was an unexpected spending in my resto budget, so if I could grab a aluminum MC for a '90 car from the scrapyard for 20$ that would help.
Next come the rebuild kit (25$ + shipping)
Then a replacement (stock looking aluminum gm MC are pretty cool for 70$)

There was so many parts that was baked or missing on this car.... *sigh*
:gurney:
 
denpo said:
Fuelie74 said:
Use a small pick to remove the snap ring that you described.

C5 master cylinder has a 1 inch bore like what came with manual brake cars not a 1 1/8 inch bore that came on power brake cars.

Stock replacement M/C for your car is cheap, why not go that route?
Click to expand...
That's what I tried, I'll try again with a sharper pick et maybe so more force.
If I would go stock replacement I would first check if the one I have is remanufacturable, because, Well, cheap is a relative measure.

Buying a new front clip was an unexpected spending in my resto budget, so if I could grab a aluminum MC for a '90 car from the scrapyard for 20$ that would help.
Next come the rebuild kit (25$ + shipping)
Then a replacement (stock looking aluminum gm MC are pretty cool for 70$)

There was so many parts that was baked or missing on this car.... *sigh*
:gurney:
Click to expand...

BTDT, and I understand you position....
but go to Pirate Jack Racing site and look for a m/cyl.....AS I RECALL mine was about 30 bux....and aluminum....so light weight...been there for about 5 years now....

:beer:
 
mrvette said:
denpo said:
Fuelie74 said:
Use a small pick to remove the snap ring that you described.

C5 master cylinder has a 1 inch bore like what came with manual brake cars not a 1 1/8 inch bore that came on power brake cars.

Stock replacement M/C for your car is cheap, why not go that route?
Click to expand...
That's what I tried, I'll try again with a sharper pick et maybe so more force.
If I would go stock replacement I would first check if the one I have is remanufacturable, because, Well, cheap is a relative measure.

Buying a new front clip was an unexpected spending in my resto budget, so if I could grab a aluminum MC for a '90 car from the scrapyard for 20$ that would help.
Next come the rebuild kit (25$ + shipping)
Then a replacement (stock looking aluminum gm MC are pretty cool for 70$)

There was so many parts that was baked or missing on this car.... *sigh*
:gurney:
Click to expand...

BTDT, and I understand you position....
but go to Pirate Jack Racing site and look for a m/cyl.....AS I RECALL mine was about 30 bux....and aluminum....so light weight...been there for about 5 years now....

:beer:
Click to expand...
Thanks Gene, will check this out tonite. :beer::beer:
 
denpo said:
mrvette said:
denpo said:
Fuelie74 said:
Use a small pick to remove the snap ring that you described.

C5 master cylinder has a 1 inch bore like what came with manual brake cars not a 1 1/8 inch bore that came on power brake cars.

Stock replacement M/C for your car is cheap, why not go that route?
Click to expand...
That's what I tried, I'll try again with a sharper pick et maybe so more force.
If I would go stock replacement I would first check if the one I have is remanufacturable, because, Well, cheap is a relative measure.

Buying a new front clip was an unexpected spending in my resto budget, so if I could grab a aluminum MC for a '90 car from the scrapyard for 20$ that would help.
Next come the rebuild kit (25$ + shipping)
Then a replacement (stock looking aluminum gm MC are pretty cool for 70$)

There was so many parts that was baked or missing on this car.... *sigh*
:gurney:
Click to expand...

BTDT, and I understand you position....
but go to Pirate Jack Racing site and look for a m/cyl.....AS I RECALL mine was about 30 bux....and aluminum....so light weight...been there for about 5 years now....

:beer:
Click to expand...
Thanks Gene, will check this out tonite. :beer::beer:
Click to expand...

Shit, one thing to know, the long dick boosters had a shaft that stuck into a hole in the m/cylinder pistons by about a inch or so, the later sharks had just a divot in the m/cyl pistons, and a short dick booster....

so look at what your car has....I forget the change over point.....

you can cut the dick off, but if you going Hydro boost, AFAIK they are all short dick versions....so just the divot...'

:shocking::beer:
 
Fuelie74 said:
Use a small pick to remove the snap ring that you described.
Click to expand...
Snap ring removed, the little bastard needed a good wack. Took out the assembly, look in good shape, but the amount of :crap: in it was astonishing.
 
denpo said:
Fuelie74 said:
Use a small pick to remove the snap ring that you described.
Click to expand...
Snap ring removed, the little bastard needed a good wack. Took out the assembly, look in good shape, but the amount of :crap: in it was astonishing.
Click to expand...

I have total example of two, and so my statistical universe is hardly large.....

but both of my used units were totally clean....

:clobbered::nuts:
 
Here's what I found at the scrapyard.
15$, out of a '02 GrandAm

16554d58ddb8b502d.jpg

16554d58ddb9a65be.jpg

Hey 69427, any detail on the SAE/Metric convertion?
I Hope the angle on the reservoir won't be a problem.
 
denpo said:
Here's what I found at the scrapyard.
15$, out of a '02 GrandAm

16554d58ddb8b502d.jpg

16554d58ddb9a65be.jpg

Hey 69427, any detail on the SAE/Metric convertion?
I Hope the angle on the reservoir won't be a problem.
Click to expand...

On the Corvette m/c the output port threads were two different metric sizes. One size is common enough that parts stores have hard lines you can buy to fit that (port) thread. The other port thread was pretty much non-existent in any parts store (and brake shop) I stopped at. I then contacted the guy that I bought the m/c from and paid him a few bucks for the original lines so I could get the threaded nut from one of the lines. I bought two metric lines from the parts store, cut the lines to length, slid the "rare" nut on one of the lines and then put the SAE double flare on the other end to match up with brake distribution block. So, metric on the m/c ends, SAE on the junction block ends.
I don't know the specifics of your new m/c (other than I'm assuming the threads are metric) so you'll have to let us know if you run into something unusual in the conversion.
Keep us posted!
 
69427 said:
Hey 69427, any detail on the SAE/Metric convertion?
I Hope the angle on the reservoir won't be a problem.
Click to expand...

On the Corvette m/c the output port threads were two different metric sizes. One size is common enough that parts stores have hard lines you can buy to fit that (port) thread. The other port thread was pretty much non-existent in any parts store (and brake shop) I stopped at. I then contacted the guy that I bought the m/c from and paid him a few bucks for the original lines so I could get the threaded nut from one of the lines. I bought two metric lines from the parts store, cut the lines to length, slid the "rare" nut on one of the lines and then put the SAE double flare on the other end to match up with brake distribution block. So, metric on the m/c ends, SAE on the junction block ends.
I don't know the specifics of your new m/c (other than I'm assuming the threads are metric) so you'll have to let us know if you run into something unusual in the conversion.
Keep us posted![/QUOTE]

Yeh, U right man, I have most always had to adapt the typical store lines to the GM fittings....some times even using a brass adapter fitting...

which is why I bought a double flare tool kit years ago.....tired of the battles, so decided to roll my own.....

:clobbered:;)
 
69427 said:
denpo said:
Here's what I found at the scrapyard.
15$, out of a '02 GrandAm

16554d58ddb8b502d.jpg

16554d58ddb9a65be.jpg

Hey 69427, any detail on the SAE/Metric convertion?
I Hope the angle on the reservoir won't be a problem.
Click to expand...

On the Corvette m/c the output port threads were two different metric sizes. One size is common enough that parts stores have hard lines you can buy to fit that (port) thread. The other port thread was pretty much non-existent in any parts store (and brake shop) I stopped at. I then contacted the guy that I bought the m/c from and paid him a few bucks for the original lines so I could get the threaded nut from one of the lines. I bought two metric lines from the parts store, cut the lines to length, slid the "rare" nut on one of the lines and then put the SAE double flare on the other end to match up with brake distribution block. So, metric on the m/c ends, SAE on the junction block ends.
I don't know the specifics of your new m/c (other than I'm assuming the threads are metric) so you'll have to let us know if you run into something unusual in the conversion.
Keep us posted!
Click to expand...
Good thing with help-yourself-scrapyard is that you can take what you want, so I took the line going with it. No sure I'll do the flares myself, I mean brakes are quiet a critical component and my flaring skill is not up to the task yet.
 
denpo said:
69427 said:
denpo said:
Here's what I found at the scrapyard.
15$, out of a '02 GrandAm

16554d58ddb8b502d.jpg

16554d58ddb9a65be.jpg

Hey 69427, any detail on the SAE/Metric convertion?
I Hope the angle on the reservoir won't be a problem.
Click to expand...

On the Corvette m/c the output port threads were two different metric sizes. One size is common enough that parts stores have hard lines you can buy to fit that (port) thread. The other port thread was pretty much non-existent in any parts store (and brake shop) I stopped at. I then contacted the guy that I bought the m/c from and paid him a few bucks for the original lines so I could get the threaded nut from one of the lines. I bought two metric lines from the parts store, cut the lines to length, slid the "rare" nut on one of the lines and then put the SAE double flare on the other end to match up with brake distribution block. So, metric on the m/c ends, SAE on the junction block ends.
I don't know the specifics of your new m/c (other than I'm assuming the threads are metric) so you'll have to let us know if you run into something unusual in the conversion.
Keep us posted!
Click to expand...
Good thing with help-yourself-scrapyard is that you can take what you want, so I took the line going with it. No sure I'll do the flares myself, I mean brakes are quiet a critical component and my flaring skill is not up to the task yet.
Click to expand...

I have a simple double flaring tool from K/D tools, I think, anyway, it's a pretty simple operation, you can see if you screw it up or not, not rocket science.....:harhar::bounce:
 
It looked odd, so I checked and that MC only has a bore of 24 mm or 0.94 inches.
OEM sizes are 1" for manual and 1.125" for boosted.
I haven't used a 1" MC on a Hydroboost, just bigger ones, so I don't know if that will result in a lower than normal pedal or not. I'm sure the end hydraulic pressure would be fine with the HB.
Considering all the added BS with the fittings, I would choose another. One other downside is the bubble flare, ISO or SAE both have a limited lifetime.

Here are a couple of alum masters that use the SAE double flare. The 1/2"-20 and 9/16"-18 flare nuts are reuseable from your old lines (as may be your complete lines) and are common to all GM of that era. Most parts stores have them.

Same bore as the OEM power master:
1990 Chevrolet Truck K2500 3/4 Ton 4WD - Pickup
Brake Master Cylinder Bore Size : 1.125"
Brake Master Cylinder Line Thread Size : 1/2"-20, 9/16"-18

Whopping Bore
2005 Chevrolet Truck Silverado 2500HD 3/4 Ton
Brake Master Cylinder Bore Size : 37 mm (1.46 inch) :amazed:
Brake Master Cylinder Line Thread Size : 2 x 1/2"-20 (double flare)

A couple months ago, in an attempt to lessen the softness of the stock pedal and increase the pedal height, I tried a number of master cylinder combinations. It involved making a new pushrod for the common newer short mc pistons and making several sets of MC to combo valve lines. I used all rebuilt cylinders because of price and probably still spent 75 bucks in fluid alone.
I didn't try the NMC P2903 (got sick of bleeding brakes etc), but I would say that combined with the HB, it would be the ultimate for a combination of maximum hydraulic pressure and high pedal. With a regular vacuum booster, it should provide a fairly stiff high pedal, like modern power brakes, if not more firm.

I ended up being satisfied with a 1-1/4" master and it's really hard to tell from stock in appearance, but it is cast iron.
 
I forget the bore dia. on the m/cyl I had on my '72 shark, when doing the HB conversion, but it was a much larger bore....I want to say 1.125 or maybe it was 1.25 at any rate, without pulling any brake lines, I put the HB in place, reinstalled the m/cyl and noted that sharkey had brakes for the first time....in fact a little TOO much brakes, in fact it would slam my nose into the wheel....

so back to a stock diameter m/cyl.....

I fought that soft crap GM stock pedal feel on the camper too, put in the LARGEST industrial m/cyl I could find about 50 lbs of 1 5/16? bore...larger than 1.25 anyway.....and found it better but IMO, vacuum sux.....so went HB one more time, man I can actually stop that camper now...all 8000 Gross VW of it, course having FORD brakes on the GM floating axle does help....about a 30% increase in swept area.....:harhar:

:goodevil::harhar:
 
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