Time to talk Brakes!

[Petescj]

Ive been driving the 81 Laredo back and forth for a little while now and working out some bugs. This Cj was bought with the intentions of Vicki driving it. She would now but the brake pedal has to be pressed harder than shed like to stop it. The backround on it is it has disc up front and of course drum in the rear. It also has manual brakes, no booster to assist.

Id like to add power brakes to it. Im looking for input from everyone on the best brake mods theyve done. Stopping a Cj on 35s is a bit taxing for the factory set up. I wont throw discs on the rear or anything but input is appreciated.

 

[73CJ]

When I went 4wheel discs I put new rotors and calipers on. I don't want power brakes. I almost go through the windshield now on a hard stop.

Make sure the rotors, pads and calipers are in good shape. The calipers can freeze and cause bad things to happen.

 

[priceg]

For the quick easy and cheap, its hard to beat a yj booster and mc setup.

 

[IOPort51]

rear disks are better than drums but the power boost ROCKS!!

by themselves rear disks were better but to stop 35s I would want the booster. especially if we are talking about a female driver. Not being sexist just being real, has she tried it as is?

 

[Petescj]

For the quick easy and cheap, its hard to beat a yj booster and mc setup.

Any specifics on this? Certain years or anything. I know the Cj style had a special bracket. I actually have one from a Yj sitting here. Came on a tub I bought.

When I went 4wheel discs I put new rotors and calipers on. I don't want power brakes. I almost go through the windshield now on a hard stop.

Make sure the rotors, pads and calipers are in good shape. The calipers can freeze and cause bad things to happen.

Rear wheel discs will probably go in at some point but not now. When I decide to do an 8.8 though...

rear disks are better than drums but the power boost ROCKS!!

by themselves rear disks were better but to stop 35s I would want the booster. especially if we are talking about a female driver. Not being sexist just being real, has she tried it as is?

Yes she tried it as is. Hence this thread. You do have to lay into them pretty hard to get a quicker stop. Too much for her. Its the only thing really keeping her out of it right now. Hmmmm... maybe I should leave it be. No honestly I want her to enjoy this one.

 

[IOPort51]

I know, it's just me but I have a problem using used parts for brakes. I would want a new booster and MC.

 

[tarry99]

Ive been driving the 81 Laredo back and forth for a little while now and working out some bugs. This Cj was bought with the intentions of Vicki driving it. She would now but the brake pedal has to be pressed harder than shed like to stop it. The backround on it is it has disc up front and of course drum in the rear. It also has manual brakes, no booster to assist.

Id like to add power brakes to it. Im looking for input from everyone on the best brake mods theyve done. Stopping a Cj on 35s is a bit taxing for the factory set up. I wont throw discs on the rear or anything but input is appreciated.

First off have you looked at the rotors and pucks on the front and the drums & the shoes on the back?........when I say that are they in good condition? Worn shoes will require more travel at the pedal while worn or glazed rotors and caliper linings will also require more force to stop!

Manual brakes normally require about 75-100 lbs of force at the pedal when everything is correct. You can get a more aggressive lining for the disc's up front which will help some.
A standard dual 8 inch booster will work although you do need about 20 inches of vacuum to supply that.

But now for the fun. Your stock pedal ratio for a manual system is about 6.6:1 The stock ratio for your Jeep with a power boosted system is about 4.5:1.
If you were to power boost your system you would want to change the ratio at the pedal ........otherwise the now power boosted pedal becomes very touchy to the touch with the increased mechanical advantage of the manual system.......(although some folks like that touchy pedal , while others complain about it , take the booster off not knowing that the real issue was the pedal ratio)
Some stock brake pedals had two holes in the pedal one at 2.5" and the other at 3.5".......but this was just the factory making a single pedal to work for both applications........the key is even if you can relocate to the second hole that position in reference to the Master Cylinder center line is now not in line with the push rod anymore. Confusing but not really if you look at it closely.......
In some cases the Linkaged Looking adapter that you sometimes see between the firewall and Booster can sometimes correct that by reducing the ratio. But the adapter adds a lot of distance forward so brake lines also need to be modified.........notwithstanding adding the booster in its current position can sometimes contact the hood.
If you have the opportunity to see a Stock power boosted system along side yours its easy to see the differences.
This can all be accomplished as long as you understand the correct path to get there.

 

[Supertrunk]

I've got a factory-stock 81 CJ7 Laredo , I-6, with power brakes. If there are any specific pictures you would like shot, let me know, and I'll get then posted up.

 

[Petescj]

First off have you looked at the rotors and pucks on the front and the drums & the shoes on the back?........when I say that are they in good condition? Worn shoes will require more travel at the pedal while worn or glazed rotors and caliper linings will also require more force to stop!

Manual brakes normally require about 75-100 lbs of force at the pedal when everything is correct. You can get a more aggressive lining for the disc's up front which will help some.
A standard dual 8 inch booster will work although you do need about 20 inches of vacuum to supply that.

But now for the fun. Your stock pedal ratio for a manual system is about 6.6:1 The stock ratio for your Jeep with a power boosted system is about 4.5:1.
If you were to power boost your system you would want to change the ratio at the pedal ........otherwise the now power boosted pedal becomes very touchy to the touch with the increased mechanical advantage of the manual system.......(although some folks like that touchy pedal , while others complain about it , take the booster off not knowing that the real issue was the pedal ratio)
Some stock brake pedals had two holes in the pedal one at 2.5" and the other at 3.5".......but this was just the factory making a single pedal to work for both applications........the key is even if you can relocate to the second hole that position in reference to the Master Cylinder center line is now not in line with the push rod anymore. Confusing but not really if you look at it closely.......
In some cases the Linkaged Looking adapter that you sometimes see between the firewall and Booster can sometimes correct that by reducing the ratio. But the adapter adds a lot of distance forward so brake lines also need to be modified.........notwithstanding adding the booster in its current position can sometimes contact the hood.
If you have the opportunity to see a Stock power boosted system along side yours its easy to see the differences.
This can all be accomplished as long as you understand the correct path to get there.

Thats alot to digest. I havent even had the wheels off yet to check and see what condition of everything is. I also never wouldve thought about pedal ratio. She may even like a touchier pedal , that would have to be seen.

I've got a factory-stock 81 CJ7 Laredo , I-6, with power brakes. If there are any specific pictures you would like shot, let me know, and I'll get then posted up.

I appreciate the offer and if I do I'll ask. I have an 83 Limited in my driveway that has the power brake set-up. Hopefully we're not at 95* today and I'll be able to see some of what Tarry explained.

 

[Petescj]

Its still stinkin hot here today but I got a couple comparison photos for anyone else who may be watching. Heres what the Laredo looks like now. Manual brakes and pretty much stock everything including the air cleaner.



This is the setup from the Limited . It has the booster and the bracket that Tarry99 were talking about.



I didnt notice how much of a difference there was in length till I started taking these pics. I took these two pics for that reason. Use the inner fenderwell as a reference for the added length.

Laredo :



Limited :



Im going to take the wheels off and see what I have. Its quiet and there isnt any tell tail metal on metal signs of worn parts, but seeing is believing. I dont mind buying the new lines , master cylinder and booster if shes still uncomfortable after I redo the brakes themselves.

 

[IOPort51]

that air cleaner goes away with the booster. It is a two objects in the same space at the same point in time problem. I am running a 7" K&M. I am sure you have seen these before but...

 

[Petescj]

that air cleaner goes away with the booster. It is a two objects in the same space at the same point in time problem. I am running a 7" K&M. I am sure you have seen these before but...

Im thinking about springing for this:

Dave's Customs Unlimited: Jeep CJ and YJ Power Brake Conversion Kit

 

[jim mallon]

Pete How goes Power Brakes ?
Found cheaper New Convert kits than Daves.

Brakes

 

[Peanut Butter]

But now for the fun. Your stock pedal ratio for a manual system is about 6.6:1 The stock ratio for your Jeep with a power boosted system is about 4.5:1.
If you were to power boost your system you would want to change the ratio at the pedal ........otherwise the now power boosted pedal becomes very touchy to the touch with the increased mechanical advantage of the manual system.......

Wouldn't using the proportioning valve from the donor vehicle (Like a TJ) resolve this problem? Rod

 

[Petescj]

Pete How goes Power Brakes ?
Found cheaper New Convert kits than Daves.

Brakes

Thanks Jim. Everything went awry from when I first posted this. It ended with a local shop doing the brakes for way too much money and not much improvement. Ive been collecting steering upgrades for a little while now and saving for tires as well. Once thats all sorted out I'll go back to the brakes.

I did save the link.

 

[ThisGuyUKnow]

Thanks Jim. Everything went awry from when I first posted this. It ended with a local shop doing the brakes for way too much money and not much improvement. Ive been collecting steering upgrades for a little while now and saving for tires as well. Once thats all sorted out I'll go back to the brakes.

I did save the link.

So long as your disks and drum componenets are in good condition. This can be done for under 100 bucks.
http://www.jeep-cj.com/forums/f2/hydroboost-install-pics-7406/

I could't find a yj with a dual diaphram brakebooster when I went to the Junkyard so I grabbed another hydroboost for my new cj. When I ran that on my Limited with 31s I had no complaints and they are supposed to really brake well with 35s

More info
Hydroboost your FSJ, CJ/YJ, Commando, M715, Bronco, IH, S10, C3, FJ40 for $125+, TX - International Full Size Jeep Association

 

[BlackOmega]

A few things I found out as I am also adding power brakes to the CJ. Instead of using a YJ booster or anything, I managed to find a donor booster at a scrap yard for $25 and used that as the core on the remanned one I bought. So I'll be using the factory CJ booster.

As far as the rest of the braking system, everything is the same from power to manual brakes. The calipers, wheel cylinders, master, etc. all use the same parts.

Good thing I found this thread, not trying to hijack or anything, but does anyone know where I can find that bracket that goes between the firewall and the booster?

 

[ThisGuyUKnow]

A few things I found out as I am also adding power brakes to the CJ. Instead of using a YJ booster or anything, I managed to find a donor booster at a scrap yard for $25 and used that as the core on the remanned one I bought. So I'll be using the factory CJ booster.

As far as the rest of the braking system, everything is the same from power to manual brakes. The calipers, wheel cylinders, master, etc. all use the same parts.

Good thing I found this thread, not trying to hijack or anything, but does anyone know where I can find that bracket that goes between the firewall and the booster?

I have one. I just pulled the cj power booster. You can buy the whole booster assembly from me and take the bracket and resell the booster if you already have the remanned booster. or jeep it as a spare.