88 YJ power brakes and master cyinder coversion, proportioning valve help??? - Pirate4x4.Com : 4x4 and Off-Road Forum
 
Pirate4x4.Com : 4x4 and Off-Road Forum  

Go Back   Pirate4x4.Com : 4x4 and Off-Road Forum > Brand Specific Tech > Jeep - Hardcore Tech
Notices

Reply
 
Share Thread Tools Display Modes
Old 02-20-2011, 12:48 AM   #1 (permalink)
Registered User
 
Swatcop's Avatar
 
Join Date: Jan 2011
Member # 178698
Location: North Beach, MD
Posts: 52
Question 88 YJ power brakes and master cyinder coversion, proportioning valve help???

Ok, I recovering from a back surgery and getting my parts together to work on one of my YJ's that I picked up a few months back. I need some advice on a proportioning valve.

Basically I am swaping in a power brake booster from a 92 YJ (no power brakes before), with a new E350 Master Cylinder. I am leaning towards putting in a Wilwood adjustable disc brake proportioning valve so I can adjust it manually (summits link http://www.summitracing.com/parts/WI...1179/?rtype=10 ) or I can go to the junk yard and find and rip out a stock YJ proportioning valve. Any oppinions on these options. Either way I go is not really too expensive, I have all of the parts except for the proportioning valve.

This YJ is sitting on Dana 60's with discs on all 4 wheels and had crap for braking due to no power brakes and only getting single lines connected to a tee in the front and rear so I am beefing it up. Thanks for the help!!!
Swatcop is offline   Reply With Quote
Old 02-20-2011, 05:30 AM   #2 (permalink)
Registered User
 
Join Date: Jan 2007
Member # 85468
Location: Richmond VA
Posts: 246
I have the Wilwood prop valve on my set up, but have it all the way open. I have a 78 Corvette master cylinder for 4 wheel disc. I have the org prop valve still on my 81 CJ, but it has been gutted and plugged the hole on the screw in part. I also have hydroboost so it stops pretty good on 1 tons & 42"s. Do a little more searching, I believe the E350 MC is better for disc/drum set up. I may be wrong, but most run the corvette or Marquis mc w 4wheel disc. Good luck. I about pulled all my hair out til I got it right.
Malibu is offline   Reply With Quote
Sponsored Links
Old 02-20-2011, 06:51 AM   #3 (permalink)
Registered User
 
Join Date: Oct 2004
Member # 37184
Location: Santa Barbara, CA
Posts: 1,327
Also rethink using the '92 booster. I'm pretty sure it's a single diaphragm unit. If you're going to the trouble of up-grading your brakes, at least include a newer dual-diaphragm booster. As I recall, they started installing them in Jeeps '95 and latter. Search: there are numerous threads covering your intended mods.
__________________
88XJ, Chevy 5.7L, Edelbrock MPFI, NV4500, Atlas, D44's, high steer, ARB's, 7" custom semi long-arm 3 or 4-link lift, BFG 33x12.5-15's.
Bubba_Jeep is offline   Reply With Quote
Old 02-20-2011, 09:19 AM   #4 (permalink)
Registered User
 
Swatcop's Avatar
 
Join Date: Jan 2011
Member # 178698
Location: North Beach, MD
Posts: 52
Quote:
Originally Posted by Malibu View Post
I have the Wilwood prop valve on my set up, but have it all the way open. I have a 78 Corvette master cylinder for 4 wheel disc. I have the org prop valve still on my 81 CJ, but it has been gutted and plugged the hole on the screw in part. I also have hydroboost so it stops pretty good on 1 tons & 42"s. Do a little more searching, I believe the E350 MC is better for disc/drum set up. I may be wrong, but most run the corvette or Marquis mc w 4wheel disc. Good luck. I about pulled all my hair out til I got it right.
I went back and forth on the master cylinder for the exact same reason because it was a disc/ drum MC. After more research than I ever want to do again I found out (or at least think I got a right answer) is that this setup should work fine but the proportioning valve will make the difference.

The next deciding fact of going with this setup was that I had all of the parts here already and they were going to be for my other YJ build (the real project) but I decided to use them for this since they were readily available and this YJ just popped into my life (GFs and wives love that stuff). I have found that there are some guys running this setup but the proportioning valves always seem to be the issue, I went back and forth on gutting mine then I saw the one on Summit for $56 and thought it may work better since I could adjust the pressure.

You are right though, there are a lot of guys that prefer and do run your setup since the MC was intended disc/ disc. So I will be honest if it all fails I give you first right to say I told ya so, LOL.

I'm am very glad to see that someone else is using this proportioning valve though. I'm thinking with the E350 MC I may have to hold a tad more pressure on the rears but I think it will work good I just wanted to see what others were thinking. I think the reason you can run yours wide open is because your MC is balanced for disc/ disc. I figure at this point even if it does not work as well as I hope I'm not going to be out anything and then I'll just get another MC.




Quote:
Originally Posted by Bubba_Jeep View Post
Also rethink using the '92 booster. I'm pretty sure it's a single diaphragm unit. If you're going to the trouble of up-grading your brakes, at least include a newer dual-diaphragm booster. As I recall, they started installing them in Jeeps '95 and latter. Search: there are numerous threads covering your intended mods.
You are right, it is a single diaphragm unit. I had considered going with a dual but the issue came down to availability in my area and then the issue of having to ensure that it seals perfectly with a MC. Jeeps in junkyards here are hard to find. I did a lot of research on the differences between a single and a dual and as confusing as brake systems can be I think I decided that there weren't as enough benefits to going with a dual diaphragm booster that would make it worth the time and money. Then again like I said above I have all of the parts here in my garage ready to go minus the proportioning valve so even if this brake conversion goes South I'm really not out anything and then I would be able to rationalize tracking down and buying a dual booster and a Mercury or Vette MC for my setup.
Swatcop is offline   Reply With Quote
Old 02-20-2011, 04:17 PM   #5 (permalink)
Registered User
 
Join Date: Oct 2004
Member # 37184
Location: Santa Barbara, CA
Posts: 1,327
I'm not at all convinced that you will improve your brakes by installing the E350 MC. The one I've seen used ("on the web") is generally the 1.250 bore unit--probably way too much volume for your calipers, and especially mounted to a single-booster. The dual booster gives you a significant amount of additional boost--almost double over the single diaphragm unit. Even then, the 1.25 MC will probably push too much fluid, significantly reducing the pressure to the calipers; nice hard and high pedal, but no stoppy!
If you run smaller calipers on the rear axle, versus the front, you may not need a proportioning valve. The valve, as I'm sure you are aware, is only intended to reduce rear braking, vs front, under moderate-to-hard braking. The MC Malibu, in the above post, is using is probably 1.125. I used the '78 Mercury unit from a hydro-boost, 4-wheel disc car, which was also 1.125. It worked well with my 2.934OD piston calipers in the front, along with the 2.12OD piston calipers in the rear; any MC larger than the 1.125 I'm using would probably reduce my stopping power. The Mercury MC required "0" mods to install against my old '88 booster. I have since switched to a dual-booster from a late model Cherokee, and to a 1.125 MC from a '03 Dodge, Durango. Braking is much improved, but that's due entirely to switching to the dual booster. You may have "stuff" laying around you're garage that you can install now, but you'd probably be much happier with the results if you re-think it.
__________________
88XJ, Chevy 5.7L, Edelbrock MPFI, NV4500, Atlas, D44's, high steer, ARB's, 7" custom semi long-arm 3 or 4-link lift, BFG 33x12.5-15's.
Bubba_Jeep is offline   Reply With Quote
Old 02-20-2011, 05:12 PM   #6 (permalink)
Registered User
 
Join Date: Aug 2008
Member # 119162
Location: Columbia,SC
Posts: 90
Is this a trail only rig or used on the road also? If it is a trail dedicated rig, a proportioning valve serves no purpose. When you are locked in 4wd, both driveshafts are obviously rotating at the same speed, and a proportioning valve can only decrease available braking power. Think about it. Even if the rig sees occasional street use, with the size tires we are running, most disc setups are overworked and the normally smaller rear discs are there own limiting factor.

By the way, I am in a Cherokee running 60's and 40" tires. I use a 96 booster and master cylinder, a disabled proportioning valve, 4 wheel discs and have excellent pedal feel and effort. The off-road braking is outstanding and on the occasions that I drive it on the street, I can stop much harder than I care to, with complete control.

Just my 2 cents.
__________________
Yes, I do have an addiction to Jeeps, and uncontrollable urges to play in the dirt.

Last edited by millerlight; 02-20-2011 at 05:19 PM.
millerlight is offline   Reply With Quote
Old 02-20-2011, 07:01 PM   #7 (permalink)
Registered User
 
Swatcop's Avatar
 
Join Date: Jan 2011
Member # 178698
Location: North Beach, MD
Posts: 52
Quote:
Originally Posted by millerlight View Post
Is this a trail only rig or used on the road also? If it is a trail dedicated rig, a proportioning valve serves no purpose. When you are locked in 4wd, both driveshafts are obviously rotating at the same speed, and a proportioning valve can only decrease available braking power. Think about it. Even if the rig sees occasional street use, with the size tires we are running, most disc setups are overworked and the normally smaller rear discs are there own limiting factor.

By the way, I am in a Cherokee running 60's and 40" tires. I use a 96 booster and master cylinder, a disabled proportioning valve, 4 wheel discs and have excellent pedal feel and effort. The off-road braking is outstanding and on the occasions that I drive it on the street, I can stop much harder than I care to, with complete control.

Just my 2 cents.

Dual purpose rig street and trail, I'm running 44's on it. You are using a dual diaphragm booster and MC from a stock 96 YJ?
Swatcop is offline   Reply With Quote
Old 02-20-2011, 07:33 PM   #8 (permalink)
Registered User
 
Swatcop's Avatar
 
Join Date: Jan 2011
Member # 178698
Location: North Beach, MD
Posts: 52
Quote:
Originally Posted by Bubba_Jeep View Post
I'm not at all convinced that you will improve your brakes by installing the E350 MC. The one I've seen used ("on the web") is generally the 1.250 bore unit--probably way too much volume for your calipers, and especially mounted to a single-booster. The dual booster gives you a significant amount of additional boost--almost double over the single diaphragm unit. Even then, the 1.25 MC will probably push too much fluid, significantly reducing the pressure to the calipers; nice hard and high pedal, but no stoppy!
If you run smaller calipers on the rear axle, versus the front, you may not need a proportioning valve. The valve, as I'm sure you are aware, is only intended to reduce rear braking, vs front, under moderate-to-hard braking. The MC Malibu, in the above post, is using is probably 1.125. I used the '78 Mercury unit from a hydro-boost, 4-wheel disc car, which was also 1.125. It worked well with my 2.934OD piston calipers in the front, along with the 2.12OD piston calipers in the rear; any MC larger than the 1.125 I'm using would probably reduce my stopping power. The Mercury MC required "0" mods to install against my old '88 booster. I have since switched to a dual-booster from a late model Cherokee, and to a 1.125 MC from a '03 Dodge, Durango. Braking is much improved, but that's due entirely to switching to the dual booster. You may have "stuff" laying around you're garage that you can install now, but you'd probably be much happier with the results if you re-think it.
This is what I hate about braking systems and this is exactly why I am not an engineer, my head is hurting again . It works in my head just fine looks like I'm going to have to rethink this again.

So if you were me besides the dual diaphragm booster tell me exactly which MC you would run with it. What vehicles would I be able to harvest a DD booster from besides a 95 YJ and newer. As for which calipers are on this YJ I have no idea from the looks of the rear I would say they are the old Cadillac Elderado ones and the front is most likely stock for a mid 80's Chevy Dana 60. I got this YJ on a trade for a Ford 8.8 and a D44 and some springs. It is solid the kid was an idiot and didn't know how to wire things up to get it running, he could bolt stuff together and that was about it.... Anyways that is a little back story on why I don't know what here I have plus I've been confined to a damn hospital bed and this is my 1st week back on my feet since my spinal fusion so I haven't had my alone time to work on it yet either....

Brake systems are a pain in the ass by the way!!!
Swatcop is offline   Reply With Quote
Old 02-20-2011, 10:09 PM   #9 (permalink)
Registered User
 
Join Date: Oct 2004
Member # 37184
Location: Santa Barbara, CA
Posts: 1,327
You probably should try a Google search for "jeep yj" +"dual diaphragm booster", as an example, to find what year/model boosters to get. I can only guess at what actually fits a YJ, since I've spent most of my time worrying about an XJ; however, brake basics are the same, no matter what vehicle.
Here's one site that you can start with. Start at post #6: /forum/jeep-non-hardcore/740128-yj-booster-question.html
__________________
88XJ, Chevy 5.7L, Edelbrock MPFI, NV4500, Atlas, D44's, high steer, ARB's, 7" custom semi long-arm 3 or 4-link lift, BFG 33x12.5-15's.
Bubba_Jeep is offline   Reply With Quote
Old 02-21-2011, 05:01 PM   #10 (permalink)
vayacondios
 
beefdawg's Avatar
 
Join Date: Feb 2007
Member # 87698
Location: nor cal
Posts: 1,281
I'm running a 90 yj single diaphragm booster with a vette m/c, summit adjustable proportioning valve, over a front d60 with dual piston calipers and rear 14 bolt with 3/4 ton chevy calipers and it stops just fine. The e350 m/c is a common conversion, just delete the stock proportioning valve.

There are quite a few threads in hardcore and non hardcore concerning this very subject. You should be able to find them with little effort.
__________________
----
80 cjunk7, with stuff--SOLD
new build... 90 yjunk, longer, wider, more stuff,

fasten your seat belt, it makes it harder for the aliens to suck you out of your rig
----

NRA LIFE MEMBER

----
beefdawg is offline   Reply With Quote
Old 02-23-2011, 11:55 PM   #11 (permalink)
Registered User
 
Swatcop's Avatar
 
Join Date: Jan 2011
Member # 178698
Location: North Beach, MD
Posts: 52
Quote:
Originally Posted by beefdawg View Post
I'm running a 90 yj single diaphragm booster with a vette m/c, summit adjustable proportioning valve, over a front d60 with dual piston calipers and rear 14 bolt with 3/4 ton chevy calipers and it stops just fine. The e350 m/c is a common conversion, just delete the stock proportioning valve.

There are quite a few threads in hardcore and non hardcore concerning this very subject. You should be able to find them with little effort.

That is the main reason I bought a E350 MC a few months ago was because all of the threads on the topic. Then after I thought that I had it all figured out (except for the proportioning valve) I asked the question you see above then I am hearing that I shouldn't go with this set up. So it left me more confused then when I started thinking about changing the brake system over in the first place. I had some of the parts already so I figured all I needed to do was either gut a stock proportioning valve or get the other one that I just ordered on Tuesday from Summit.

Brakes turn into touchy subjects all the time on here, lots of opinions around the web that can go either way on my planned setup. I am still thinking right now I am gonna bolt this MFer up and get it plummed and do a "real world" test and see if I like the stopping ability or not... All I have to lose at this point is time and effort, I can say it can't be any worse than the manual MC setup that is on it now....
Swatcop is offline   Reply With Quote
Old 02-24-2011, 10:15 AM   #12 (permalink)
Registered User
 
Join Date: Oct 2004
Member # 37184
Location: Santa Barbara, CA
Posts: 1,327
It's all about pressure exerted on the rotors/drums by the system. Your manual brake system, just as a power brake system, was designed around a specified gross vehicle weight. Meaning rotor or drum size, as well as caliper piston sizes are designed to apply sufficient mechanical pressure to stop the wheels from turning. The ratios of MC piston size-to-caliper piston size, and brake pedal ratio interact to give you the required pressure at the wheels. Fool with any of these ratios, and the effect on over all braking can be predictable, if you understand the basics of leverage. Don't listen to people who say they threw on an E350, or Dodge 3500 (both 1.25 in bores) MC's to an otherwise stock CJ/XJ/YJ ect, and got great brakes. If you increase the MC volume without increasing the caliper volume, your brakes will degrade, meaning they will be worse than they were. Just saying you installed "tons" doesn't mean the fluid volume requirements necessarily increased, or increased enough to warrant going from a 15/16 MC bore to a 1-1/4 bore (which is a 33% increase). You need to actually determine the volumes of each caliper, and calculate the actual increase in volume you have effected by your brake upgrade, to determine the necessary required change in MC volume. If you don't, you're just guessing, or accepting other peoples anecdotal comments as proven engineering. This could lead to poor and dangerous brakes. As a sanity check, look at the design of the braking system that your parts came off of, to get a "feel" regarding the size of MC designed to be used with the selected calipers. Also take into consideration the size and type of brake booster in the original system. Newer Jeep (since 1995) systems I've looked at all have 1 inch MC bores, and a dual-diaphragm 7 inch booster. You'll notice the Dodge trucks with the 1.25 MC's have a much larger booster than 7 inches--and the bigger trucks seem to go hydraulic power boosters. Why? The bigger MC's require a huge amount of foot pressure to get sufficient hydraulic pressure to the rotors. Early Corvettes, and certain Mercurys used a 1-1/8 (1.125) MC, IN CONJUNCTIN WITH HYDROBOOST. Examples for using a 1.125 MC are '79 Chevy 1/2-ton, and '79 Ford 3/4-ton trucks (with single piston brakes)--but look up the booster sizes compared to a jeeps. '79 Ford 1/2 tons used a 1 inch MC, while the front dual pistonned 3/4-ton trucks used 1-1/16 pistons. Note that when the Ford's front pistons increased in volume by 51% (front single piston to double piston calipers), Ford only increased the MC volume by 6% (from 1" to 1.06").
In the above Chevy example, some 3/4-tons came with 3.146 OD front piston. That was 7% larger than the smaller brakes available on 1/2-tons and some 3/4-tons. The MC was increased 11%.
__________________
88XJ, Chevy 5.7L, Edelbrock MPFI, NV4500, Atlas, D44's, high steer, ARB's, 7" custom semi long-arm 3 or 4-link lift, BFG 33x12.5-15's.
Bubba_Jeep is offline   Reply With Quote
Old 03-07-2011, 06:07 PM   #13 (permalink)
Registered User
 
Join Date: Feb 2006
Member # 68160
Location: San Jose, California
Posts: 153
I used the dodge 3500 mc on my 91 yj with dana 60 front dual piston calipers and 3/4 ton chevy calipers 14 bolt rear.
Works great. Minimal effort on the leg. I pushed the pedal harder to get it to stop in my old setup with stock 30/44 axles and 35'' tires. Can lock up all 4 tires doing 35 mph down my backroad.

Here's the link where i got it. The part #NM3060, which is the same part # that will show if you research a dodge 2500 as well.

http://www.autozone.com/autozone/par...8202_0_0_43445
__________________
My Build: 1tonYJ
[url]http://www.pirate4x4.com/forum/showthread.php?t=963523[/url]
fatony is offline   Reply With Quote
Old 03-07-2011, 06:08 PM   #14 (permalink)
Registered User
 
Join Date: Feb 2006
Member # 68160
Location: San Jose, California
Posts: 153
also check out this thread . . .

http://pirate4x4.com/forum/showthrea...rtioning+valve
__________________
My Build: 1tonYJ
[url]http://www.pirate4x4.com/forum/showthread.php?t=963523[/url]
fatony is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 02:23 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 ©2011, Crawlability, Inc.