Master cylinder for Blazer brake upgrade with C5 fronts and stock drum rears

81cutlass

Royal Smart Person
Feb 16, 2009
1,149
896
113
Western MN
#11
I edited my original post. I read from a few places that the s10 ones were bubble flare but they must have been wrong.

Gotta take what you read on the interwebz with a grain of salt I guess, who knew :O
 

roger1

Greasemonkey
Aug 23, 2010
183
129
43
San Angelo, TX
#12
Oct 14, 2008
9,272
2,382
113
Gainesville, Fl
#13
I can't stand the snap in plastic reservoir caps. They're noted for leaking and when you pop the cover off to inspect the fluid and reinstall them.
I do like the screw on cap type reservoir on the RHD Blazer master cylinder. That will definitely be my next master cylinder when the time comes.
 
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64nailhead

G-Body Guru
Dec 1, 2014
668
375
63
Upstate NY
#14
I just ordered the B-body ('89 Buick Electra Estate) cylinder only for the reason that it looks stock and it was cheaper than the others. I'll update when it's installed of how well, or not well, it works.

p.s. - if it doesn't work, then I'll be onto the Blazer one Turna linked.
 

64nailhead

G-Body Guru
Dec 1, 2014
668
375
63
Upstate NY
#15
I'm not a brake expert, but the B-Body wagons (like an '89 Electra) had 12" front disks. and I think the 12" single piston (3" diameter) actually has more volume than the dual piston C5/LS1 calipers (1.75" diameter).

Electra Master cylinders are like $25 on Rockauto, so It might be worth a shot.
New Raybestos (no core) down in flames - leaking from the shaft after bench bleeding. Tried to return it to Rock Auto and got declined ???!#@!? Sent them an email and we'll see how that turns out. I can see the shaft a coming for my $49, hopefully I don't feel it - lol.
 

64nailhead

G-Body Guru
Dec 1, 2014
668
375
63
Upstate NY
#17
I'm not a brake expert, but the B-Body wagons (like an '89 Electra) had 12" front disks. and I think the 12" single piston (3" diameter) actually has more volume than the dual piston C5/LS1 calipers (1.75" diameter).

Electra Master cylinders are like $25 on Rockauto, so It might be worth a shot.
^^^this^^^ will not work. The diameter of the m/c is too big to go into the booster.

But this was good for building my m/c bench bleeding skills - lol. OK Turna, I'm onto the S10 right hand drive unit. I'm going to find out how well it works with stock rear drums and proportioning valve.
 

81cutlass

Royal Smart Person
Feb 16, 2009
1,149
896
113
Western MN
#18
^^^this^^^ will not work. The diameter of the m/c is too big to go into the booster.

But this was good for building my m/c bench bleeding skills - lol. OK Turna, I'm onto the S10 right hand drive unit. I'm going to find out how well it works with stock rear drums and proportioning valve.
Odd. Wonder if the new ones/the one you got aren't made to factory specs. I got a OEM one off a car from the salvage yard and it works great.
 

64nailhead

G-Body Guru
Dec 1, 2014
668
375
63
Upstate NY
#20
Odd. Wonder if the new ones/the one you got aren't made to factory specs. I got a OEM one off a car from the salvage yard and it works great.
From doing some more reading, and looking at pictures on Rock Auto, it appears that later models might have an option for a larger bore booster to accept the master cylinder I bought. We have the double diaphragm booster that appears to be the stock '80 Cutlass 'HD' unit. But it does not interchange, according to Rock Auto with much of anything newer than an '81.

81cutlass, what year is your car that you put the larger m/c onto?

Does anyone else have a booster laying around that could be measured?

Lastly, we were thinking of swapping to the single diaphragm booster for appearance only. Is the stopping power, required foot/leg pressure varied from the double diaphragm?
 
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