Power brake upgrade question

[1970blazin]

So from what I am reading I should be fine with all the power brake stuff off of another truck- even if that truck had discs up front and I am sticking with my drums up front for now??? Is that right? Also who sells the best disc upgrade aftermarket? I have heard it is pretty expensive, but maybe worth it in the long run.
Thanks all!!
Diane

[Stepsides 4Ever]

I think what everyone is saying is to use the booster, master cylinder pushrod, and the pedal pushrod from the donor truck. Use your existing master cylinder and everything else. You may need to adjust the pushrod length...not sure of the proper procedure on that one, but if it were mine I would adjust the pushrods so that I had a very, very small amount of free play on both pushrods. For the m/c, maybe measure the distance the m/c pushrod extends from the m/c mounting area and adjust it (if needed) so that it is slightly less than its seated position in the m/c piston. If it is off by too much you may need to buy a rebuilt m/c for the power brake option, but they are not too expensive.

As to who makes the best disc brake upgrade kit, it depends on who you talk to...pretty much, you pays your money and you takes your choice. You are going to be buying off-the-shelf rotors, rebuilt calipers, and hoses, at the minimum, and for the complete setup, throw in backing plates, wheel bearings and grease seals, dust caps, and (for a 2WD truck) new spindles (couple of different options there). Figure $400 to $550 for the complete setup (I paid $400 cash from CPP at a swap meet for their OEM kit, minus the backing plates, which I got off a late '80s 'Burb at the boneyard for $15). Or you can piece something together with off-the-shelf and boneyard parts. There's a lot of ways to go on that one. If you have a 2- or 4WD Blazer, the rules change, and I have no idea what is involved with that.

[pritch]

[QUOTE=72gord]The only real difference between 1/2 and 3/4 ton brakes is the bolt pattern and when you jump up to 1 ton they are hydrauliclly powered instead of vacuum powered

So, will a booster off a 1 ton work on a 1/2 ton? Where does the hyd. come from? I want to make the switch on my '68 1/2 ton panel, and I found a booster from a '69 1 ton for free.

[72gord]

That sentence came from another post to this thread, I just didn't get the quote thing on there when I posted. But the hydraulic pressure comes from the power steering pump, not sure just how the plumbing goes or if you have to have the ps pump from a hyd. booster truck. My brother has a truck with this set up though...could check into it if you want me too. The truck he has is a 1 ton, and he is parting it out if you need something I'll ask him what he has left, it is an 81 model so the motor to pump brackets may be different.

[neonlarry]

Check out this article . You will probably need special hoses made as the newer hydraboost pumps are metric fittings I believe. Hopefully you got the rods on both ends of the booster (booster to master & booster to pedal) those will be hardest to come by if you don't have them. Bolt the boster to fire wall and master to booster (should not even have to disconnect brake lines). You will have to put a tee in your pwr steering return line for the third booster line.

[Bowtie67]

Originally Posted by Stepsides 4Ever

If disc brakes were not superior to drum brakes, manufacturers would still be offering disc brakes as an option. I don't think you will find very many vehicles produced in the last quarter century that did not come standard with disc brakes.

Car manufacturers were almost forced to go this route, If one car manufacturer offered Disk Brakes and the other didn't they would loose sales because it was a better idea. But not an absolute issue. Power drum brakes I feel will stop just about as well as disk brakes would, advantages of disk brakes better high speed cooling. For everyday in town driving or back country roads where you are doing posted speed limits is certainly not an issue for drum brakes. On the highway at high speeds and having to jump on and off the brakes in almost panic stops I'd go with disk brakes. JMO

[1970blazin]

I think we are going to end up buying a new power booster from Autozone. They are under $100 and it comes with the rod. Then we can use our existing master cylinder, right? Can you buy a new proportioning valve too, or will one from a disc front setup work on my truck?? (drums all around)
Thanks to all for the great info!!!!!!

[68w/sbc406]

is there a difference between a 1/2 ton booster and a 3/4 ton booster? i am planning on doing front disk on my truck and i have access to both

[pritch]

The booster I can get is a vaccum assist. I was under the impression ALL 1 tons had the hydro. assist. Maybe this isn't the stock booster? It rained here all day so I didn't go get it.

[neonlarry]

Diane, you can use existing drum brake master and proportioning valve if you have them. If you need a new proportioning valve you need to get drum style for drum brakes or disc for disc brakes they hold different residual pressures for the different style brakes. Drum style holds more pressure than disc style. Some people say they have not had a problem mixing one with the other but a drum style valve will make discs drag slightly and a disc style will make drums have more pedal travel.

[krazy_texan]

Originally Posted by JimKshortstep4x4

Disc and drum master cylinders are different and should be used with their respective systems. Boosters will work in either system.

Not knowing 1970blazin's situation, a power drum setup might be appropriate. We run a 70 4x4 with power drums and it stops extremely well. We don't have steep grades to contend with so fading is not an issue. I agree with CPNE, drum brakes do work well and they can be considered as an option depending on the type of driving that is done.

Jim

what is the difference because i took a master cylindar and brake booster off of a 71 disc brake truck and put it in a 67 drum truck and have no problems

[neonlarry]

The front reservoir in the disc master has a larger capacity. See my post above about proportioning valves.