I didn't doubt you! Just trying to figure out what boosters it will fit.
Is your booster stock for your K5?
Is your booster stock for your K5?
CK5
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4wheel discs, FOUND PERFECT MASTER CYLINDER!!
- Thread starter muddybuddy
- Start date
73k5blazer said:
i know, im just trying to show how it fit in mine. yea its the stock booster. everything is stock, maybe you should see how much an 88 booster costs
in my quest to find master cylinders, i went through a bunch til i found this one. as i was lookin at past threads i saw a guy put a '76 or '78 k20 one on, so i tried to get that one, but i remember the bore being too small, so i guess they did change it.
I got the master for the hydro- boost unit I got , 1ton 1995-1997 chevy pickup. (same setup in my '97 K2500 w/ 6.5 turbo diesel...it has good brakes).
Trucks not road ready yet so I can't tell how good they are. Brakes are wet though, rolling down the driveway seems to stop ok!
Trucks not road ready yet so I can't tell how good they are. Brakes are wet though, rolling down the driveway seems to stop ok!
Nice find!!!
I definately added that to my favorite tech links.
I definately added that to my favorite tech links.
Desert Rat
Fetch the comfy chair
muddybuddy said:
Well, anybody out there every bolt up a stock 88 MC to an earlier Blazer to see if it fits? I'd hate to buy one and have to return it.
Desert Rat said:
It's not that simple... there are multiple flavours of boosters on Blazers.
In your case, your truck SHOULD have the same booster I know and love (err, hate!) ... and IIRC, no, the new-style master does NOT fit the older booster, as I tried that on my Chalet.
-- A
Desert Rat..on both my K5's...76 Chalet and a 79 i used a mid 80's booster and master...all i had to do was swap the lines. Older K5's have an 7/8 bore while the later models have a 1 1/8th bore.
DW
DW
Im gonna go ahead and give this a shot, just ordered the master cylinder, it will be going on my 87...
mouse
1/2 ton status
K5er4Life said:
What is your brake setup?
i had my first real panic stop this morning, and it stopped very nicely!! im very pleased!
muddybuddy said:
As a side note, I think that hydroboost masters and vacuum masters are different and should not be mixed. I've gone through two (new, not reman) P30 masters on a vacuum booster, so while they *fit*, I'm not convinced they work real well. I think the vacuum booster actually has more throw of the piston and is popping the seals on these masters.
Your '99 C3500 above would seem to have hydroboost, so I'll be curious to see how long your master lasts, if it starts leaking after a month or two.
That said, maybe I just got some bad masters or maybe I'm an idiot
, so I'll keep my eyes open.I've also converted my truck to hydroboost, so I may try the P30 master on it once I forget how much I hate hydraulics.
-- A
well i tried a master from a k20 and it either blew the seal, or was a poor reman cuz it leaked. so far so good, ill keep my fingers crossed. in the computer is said nothing bout hydroboost for the master, but there were some for the c3500 that specified for hydroboost, so i duno. i dont think this one is for hydroboost
roadnotca said:
Yes, there is.
It boils down to simple leverage. The bigger the bore m/c the less leverage you have and the less pedal travel you have. With enough booster this doesn't matter. Enter hydroboost....
With too small of a master you have all kinds of leverage, but too much pedal travel. Some of that pedal travel is used to distort all of the other parts of the system since you can now generate excessive line pressures.
This isn't a wide ridgeline, it's nearly a knife edge. Easy to fall off too far one way or the other.
Prop valves: It's been my observation that the shorter the WB and or the taller the tire the less a p-valve is needed. Friend of mine (Dremu met him) had a nearly stock flat fender w/ 4 wheel discs. All the same size rotors & calipers running off the stock single outlet m/c. Worked great.
Also, if I understood correctly for this m/c to work you have to swap the lines front to rear & vica versa. This is not good. The front brakes should be operated by the rear piston in the m/c. If everything is working correctly it may not be a problem, but when something fails it could become one. The reason the OE arrangement has the front brakes on the rear piston is b/c this piston is directly operated by the pushrod from the pedal. The front m/c piston is actually operated by the rear m/c piston. So the rear brakes don't start to operate until after the front brakes already have some fluid pressure.
ntsqd said:
Not in order... the only brake booster I could find for a '99 C3500 was hydroboost, so I presume they're all that way.
Ntsqd is dead on with the reversed fitting thing. Many of the incorrect-application masters are this way (the P30 is backwards, for instance.) All it takes is new fittings for the ends -- 9/16" on the little line, which is what, 1/4"? and 1/2" on the big (5/16"?), IIRC -- and a double flaring tool.
-- A
roadnotca
3/4 ton status
While we are re-engineering GM brakes, has anyone tried this on surfaces other than dry asphault?
roadnotca said:While we are re-engineering GM brakes, has anyone tried this on surfaces other than dry asphault?
id think that would be the hardest to stop on.. I dont see it being tougher to lockem up in sand, mud or in the trails....!!!!!
if it can handle asphault id say it will do on rocks too
dremu said:
There's definitely differences. You should try to get a matched set, booster and MC. Bosch was a customer of ours and I used to work there for a little while, I saw the CAD models for the hydro-boost units. The throw is sometimes different between them, even using the same case casting. Your not going to be able to tell by actuating by hand either, unless you can feel 1/32" difference.
roadnotca
3/4 ton status
What I was gettin at, I suspect, would be some experimenting with the proportioning valve so front to back apply like they are supposed to, especially in ice/snow/rain/mud. Wouldn't want to test with crush zones.RootBreaker said:id think that would be the hardest to stop on.. I dont see it being tougher to lockem up in sand, mud or in the trails....!!!!!
if it can handle asphault id say it will do on rocks too
roadnotca said:While we are re-engineering GM brakes, has anyone tried this on surfaces other than dry asphault?
and thats exactly why Im not messing with the brakes on my crew cab, they work really well, and I dont mind the drums in the rear. I dont want to screw with them like I have on my blazer. When Im towing my blazer I would rather trust the gm engineer than myself when it comes to braking. The only thing I have even considered doing is allowing the pump the increase its flow. That or throw on a new ps pump because mine wines a little bit and sometimes its hard to turn while stopping hard.
And as far as what Im putting this master on it will be going on my 87 blazer with 1/2 ton calipers in the rear, 60 up front, and stock proportioning valve. I dont like the pedal travel my truck currently has, but it will stop real good...once the pedal is only about an inch from the floor!
I hadn't seen this until now. Dry asphalt is the best case scenario, ice would probably be the worst. Everything is a compromise. You can set up the truck for heavily loaded on dry pavement & know that unloaded on ice is going to be an animal to control. You can set up for unloaded on ice & know that you're giving up some loaded on dry pavement braking ability.RootBreaker said:id think that would be the hardest to stop on.. I dont see it being tougher to lockem up in sand, mud or in the trails....!!!!!roadnotca said:While we are re-engineering GM brakes, has anyone tried this on surfaces other than dry asphault?
if it can handle asphault id say it will do on rocks too
What GM is trying to do with rear only ABS, and others have done with "Load Sensing Proportioning Vavles" is to vary the rear brake pressure based on load, and in the case of ABS, both load & traction.
There's a common partial misconception about being able to lock up the brakes. The general idea seems to be that the easier you can lock up the brakes, the better the brakes are. Nothing could be further from the truth.
Brakes that are easy to lock up are miserable to drive.
What's desired is brakes that can lock up the tires, but only at the outer extreme of their performance. A skidding tire takes further to stop than a rolling one. Why? A skidding tire burns or boils off rubber. That debris ends up btwn the tire & the pavement where it effectively acts like grease.
GM does an odd thing with brake plumbing that I've not yet figured out or found the reason for. Typically the rear brakes are plumbed with 1/4" tube instead of 3/16" tube. That may not seem like much, but in one foot there is over 2 square inches additional surface area in the 1/4" tube that the 3/16" tube doesn't have. So in a 125" WB vehicle there's roughly 2 square FEET more tube interior surface area for the operating pressure to work against.
I suspect this is done to cause a delay in rear brake operation. For the volumes involved, even with the 14bff's large wheel cyls., it can't be justified by flow requirement.
