Need Chevy Disc Brake Info**fast**

[airman]

Something interesting that I found when I did mine. The PO had previously replaced the mster cylinder. I later found out when I could not find a residual valve to remove that he replaced it with a disc/drum MC.

A drum/Drum will have two chambers for fluid the same size. A disc/drum will have a small one and a big one.

 

[SaddleUp]

Something interesting that I found when I did mine. The PO had previously replaced the mster cylinder. I later found out when I could not find a residual valve to remove that he replaced it with a disc/drum MC.

A drum/Drum will have two chambers for fluid the same size. A disc/drum will have a small one and a big one.

Mine was a disk/drum one as well. It came with the duff power brakes that had been previously installed. I changed it out anyway though. I did the front disks, changed the rear brakes shoes, and replaced the master cylinder all in one shot to make sure it had good brakes. The rear shoes and the master cylinder together cost about $30.

 

[blazinchuck]

OK, now if I understand things...the bigger the bore/harder to push...right? So wouldn't it be better to use old MC without valve? I know a disc/drum MC is valve for more pressure/fluid to the front, but I'm going trail riding and want somethings fairly good. I'm not trying to go round&round, just about to spend moneys on this stuff in a couple of hours...

 

[Skuzzlebutt]

The trade off is a smaller bore M/C gives a mushy feel and requires longer pedal travel.

 

[NeverSatisfied]

OK, now if I understand things...the bigger the bore/harder to push...right? So wouldn't it be better to use old MC without valve? I know a disc/drum MC is valve for more pressure/fluid to the front, but I'm going trail riding and want somethings fairly good. I'm not trying to go round&round, just about to spend moneys on this stuff in a couple of hours...

yes you want to keep the bore size a little lower, but what you may find, and what I and some others already have experienced is the stock Drum/Drum MC will require a second pump to build enough pressure the bring the truck to a stop using chevy disks. I don't know about you, but I only like to have to press the brake one time when I want to stop my Bronco.

 

[Broncobowsher]

Both of the conversions I did I started with the stock master cylinder. The first one, that was as far as I went. The second one started a long line of experimenting.

When I did disk brake swap on Bronco #2 I left the stock master cylinder in place. (never looked for the pressure valve on any master cylinder I used). After putting the disks on and bleeding them, they worked good. They would stop and stop straight. After a couple weeks I was starting to need the double pump. Why? Because the master cylinder had rust in the bore. When bleeding it the cups traveled into the rust and they got tore up. Over the next couple weeks they just got worse. (the thing had been parked for 8 years or so before I revived it).

Being the one for experimenting, and reading up on the Internet, I got one of the F250 camper special (for the 2 piston calipers) master cylinder, 1-1/4” bore. Bolted up, might have required some parts store adaptors to match the lines to the ports. That did work. The pedal had no travel to it and you had to press very hard. But always good and predictable. Next up I tried a Mustang SVO master cylinder with a smaller 1-1/8” bore. This was an improvement. Pedal force was down, actually had some travel to it. Should have just done a stock 1” bore.

Instead of doing a 1” bore or even going the other way and trying a 15/16” bore I just went hydro. That and a 1” bore master cylinder. Now I have brakes. As for the people wary of power brakes, I can state that it stops better without assist now then it did with either of the past 2 master cylinders. With the hydro charged and running, you have super brakes.

Big bore = less travel but more effort
Small bore = more travel but less effort.

 

[gear_head]

I run a 00 Mustang hydroboost, stock MC, and Ch&*y disc conversion with stock drums in the rear. I tried the recommend "camper special" MC and ended up going back to the original as it degraded the pedal feel. This setup outstopped my '97 Expedition with rear discs.

 

[ransil]

Ok, heres the problem. I was getting ready to install the lock-right in the front. so when I pulled the drums off, I noticed the brakes were shot!. I have been collecting parts lately for the swap to GM disc, but still need inner/outer bearings and brake hoses to complete the swap.
Either I go and get new shoes and turn the drums or finish getting those items for disc brakes. I'm worried the disc wont stop as good with my stock MC. I getting this ready for a trip to NC's Uhwarrie and I just want good brakes.
The disc parts might cost $100 ver.$60 for the drum stuff. Which should I go with? Should I get a better bolt-right-in MC to help w/disc...if so I need to know the best MC that will bolt right in. Sorry this is long, just need help now-time is wasteing.

Your current bronco bearings should fit , if not you have the wrong chevy spindles.

I use the stock bronco MC, manual brakes, with 35" tires, no problems. ( pressure valve is removed).

 

[blazinchuck]

Well before I upset anyone, I just want ya'll to know how much I appreciate the help. However, I have been doing nothing but work for that last 3 days(OT), so I have lost some time on this. I did try to set the backing plate on and the calliper will hit(needs grinding). So with this in mind, I checked the drums and they are within specs and are not groved. I decided this week and 1/2 before the trail ride is not the time to do this. I know I can replace the shoes and thats it....DONE, bleed some fluid and hit the road. But the disc thing is a -try this , -then try that...dont have time for that stuff yet. So I going to focus on the other stuff so I can make the trip safely and prepared. Thanks again to everyone. When I'm not under the gun and hopefully I win the Hydro set up from TOFIC(HA HA) I can do it right.Chuck;D ;D