International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tech Archives > Suspension and Steering

Reply
 
Thread Tools Display Modes
  #1  
Old 01-12-2006, 06:18 AM
KaiserMan's Avatar
KaiserMan KaiserMan is offline
I got the Willys....
 
Join Date: Jun 21, 2005
Location: Huntington, Ma.
Posts: 8,692
Post Hydro boost install write up w/pics

Installing GM Hydro Boost brakes in a Dauntless 350 powered FSJ.

Note, this covers installing the Hydro Boost in a Jeep with a manual transmission. Installing the Hydro Boost in a Jeep with a automatic transmission will be different, as the push rod for automatic equipped Jeep's goes through the firewall in a different location.

The swap was fairly straightforward. This write up is broken down in to several sections.

All of the parts I used came off of a 1979 Chevy K-30. To my knowledge Hydro Boost systems can be found on all GM 1 ton trucks and vans, as well as on 3/4-ton Diesel
trucks.

The Booster.

On a GM, the booster is held on by 6 studs, two pressed into the booster mounting plate, and 4 pressed into the firewall. In order to mount the booster on my Jeep I had to remove the two studs pressed in to the booster plate as I was unable to mount the push rod eye onto the brake pedal stud and align them (the studs) with the holes in the firewall at the same time.

The middle two mounting holes on the booster mounting plate line up with the stock Jeep master cylinder mounting holes in the firewall. I drilled two holes through my firewall (using the booster plate as a guide) in order to use the lower mounting holes on the booster plate. The top ones cannot be used.

The top left corner of the booster plate must be cut off in order to clear the wiper motor mounting bracket.

In order to connect the booster (or even fit it into place on the firewall) the push rod must be cut down. The length of the push rod may vary from Jeep to Jeep, so I will leave this measurement out. Jeep used a larger push rod mounting stud then Chevy, so you will either have to open the Chevy push rod eye up slightly, or use the Jeep push rod eye when you weld the push rod back together. I had mine TIG welded.

It helps to have two people to install the booster, as with out the studs one must connect the push rod to the pedal stud and support the booster at the same time. I used 3/8”X 1” grade 8 bolts in place of the studs. I chose to run my bolts in from the engine side of the firewall, though it makes no apparent difference as to which way they go.


The middle bolt holes line up with the stock master cylinder mounting holes, the bottom holes need to be drilled through the firewall, and the top cannot be used.

The Pump.

One can use the stock pump by connecting the return line from the steering box to the pump to the return line from the booster to the pump with a T fitting. However since I had the Chevy pump with the two return line outlets, I decided to use it. On my pump, I had to remove the pulley in order to remove the pump mounting bracket.

Here it should be noted that my Gladiator has/had an actual Buick power steering pump and brackets. The factory Jeep power steering bracket and pump on my Wagoneer is different, so the following may or may not affect you.
In order to mount the pump, I had to swap the top left plug with the bottom right stud on the back of the pump. This stud is simply threaded in and is used as a part of the adjusting system. The Chevy pump pulley was larger then the Buick power steering pulley, however I was still able to use the belt.


The positions of the stud and the plug must be swapped. (Grimy, ain't it?)

The Master Cylinder.

Any master cylinder for the JB8 Hydro-Boost brake system should work. The one I used is a Fenco part number M1584. The ports for the brake lines are on the driver’s side of the master cylinder, as opposed to the passenger’s side of Jeep master cylinders. The GM master cylinder uses a 1/4" line for the front port, VS Jeeps 3/16”, so an adapter is necessary. Any good parts store should carry one. Mine came from NAPA and was just under $4.

On GM's the front reservoir supplies the rear brakes, and the rear reservoir supplies the front brakes. Remember this when installing your new brake lines.

GM uses a plunger style stop light switch mounted to the brake pedal arm, VS Jeeps master cylinder mounted pressure switch. I don’t care for the plunger style switch, so I plumbed my original pressure switch into my front brake line using a T style hydraulic fitting. This part should be available at all better auto parts stores. My local Auto-Zone did not carry this part. I purchased it from NAPA for just under $5 with two 3/16’ line fittings.


The master cylinder, brake line adapter and pressure switch.

Hoses.

There are three hoses that attach to the Hydro boost, the booster to pump return hose, the booster to pump pressure line and the booster to steering box pressure line.
You discard the factory steering box to steering pump pressure line, as its attaching points are used by the booster to pump pressure line, and booster to steering box pressure line.

I found two different booster to pump pressure lines. One is off a GM trucks with a small block, and the other is off a GM trucks with a big block. Either will work, however the big block hose is shorter and fits better.

The stock steering box to pump return hose fitting is smaller then the one used on GM’s. This did not affect anything as this in the one hose that stays in place (besides disconnecting it from one pump and reconnecting it the other).


As you can see, there is alot going on in this area with all the hoses attached.

Misc.

There are two brackets designed to secure the hoses, one that holds the metal part of the lines and mounts under the master cylinder attaching nuts, and one that mounts to the inner fender and holds the rubber part pf the lines. They are not necessary, however they do make routing the hoses easier, not to mention better looking.

I moved my windshield washer fluid bag to the passenger’s side inner fender (the same position Jeep mounted the bags in vehicles with power brakes). I could have left it on the drivers side, but with the brake lines now on the drivers side, and the hoses that particular are was getting crowded. A longer hose from bag to washer nipple is needed to do this.

Alternatively, one could mount the later model plastic washer fluid tank,
However the coolness factor of your washer system would be diminished


The washer bag in its new position. This is the correct location.


Overall, the finished install is pretty clean.
__________________
Thomas Russell
1975 Chevy K20 8400lb GVW Camper Special
1971 Gladiator
J2000 Platform-Stake Dump 350/T18

1970 Gladiator J3000 3407Z Camper Truck 350/T18
1963 Gladiator J300 Townside 350/TH400


Last edited by KaiserMan : 06-05-2006 at 06:47 PM.
Reply With Quote
  #2  
Old 01-12-2006, 06:31 AM
pb's Avatar
pb pb is offline
Master Mechanic
 
Join Date: Aug 28, 2003
Location: Leslie, MI 49251
Posts: 1,443
Post

Nice job, thanks!!
__________________
Paul
1975 Wagoneer DD
360 with large cap ecm controlled HEI, TBI EFI, Comp Cam 260H, Edelbrock Performer Intake, CS130 alt, 4 row radiator, S10 steering box, QT w/LO, WT 3.54 D44 axles. Rancho 9000X's, ~4" lift, Caddy rear discs.
Reply With Quote
  #3  
Old 01-12-2006, 01:18 PM
JeepsAndGuns's Avatar
JeepsAndGuns JeepsAndGuns is offline
AMC 4 OH! 1
 
Join Date: Jul 18, 2003
Location: Cullman, AL
Posts: 4,566
Post

A few questions. What year is is the truck you installed it in? Mine is a 79, I am guessing yours is an older model. Did yours have power brakes to start with or manual?

After reading your writeup there are several diffrences between my install and yours. I am thinking about makeing a writeup for mine too, just to show the diffrences. On mine the chevy rod was too long like yours, but the hole was way too big for the stud on the jeep pedal. Also on mine I had to use the stock spacer between the booster mounting plate and the firewall, because of the snout of the booster wouldnt have let me have a rod to attach to the unit. I might wait a day or too and put some pics together and make a post outlineing my install. Yours looks great! How do you like it?
__________________
79 Cherokee Chief 401/T18/D20, MPFI fuel injection, hydroboost, otherwise stock.
Future mods: Caddy 500/NV4500/NP205, HP D60 front D60 smooth botom rear, 5.13 gears, 35x12.50's on H1 beadlock wheels. Warn M12000 winch.
93 Wrangler 4.6 stroker/AX15/NP231,SYE,CV, OME 2.5 lift, front hub conversion/big brakes, 31X10.50's Warn M10000 winch.
Reply With Quote
  #4  
Old 01-12-2006, 01:37 PM
380tom's Avatar
380tom 380tom is offline
Grease Monkey
 
Join Date: Jun 11, 2005
Posts: 476
Post

Ooohhhhhh!!!! ......That's what those hooks on the side of my fender well are......Now I need a cool bag like that. Anybody got one?
Reply With Quote
  #5  
Old 01-12-2006, 02:15 PM
KaiserMan's Avatar
KaiserMan KaiserMan is offline
I got the Willys....
 
Join Date: Jun 21, 2005
Location: Huntington, Ma.
Posts: 8,692
Post

JeepsAndGuns wrote.

Quote:
A few questions. What year is is the truck you installed it in? Mine is a 79, I am guessing yours is an older model. Did yours have power brakes to start with or manual?

After reading your writeup there are several diffrences between my install and yours. I am thinking about makeing a writeup for mine too, just to show the diffrences. On mine the chevy rod was too long like yours, but the hole was way too big for the stud on the jeep pedal. Also on mine I had to use the stock spacer between the booster mounting plate and the firewall, because of the snout of the booster wouldnt have let me have a rod to attach to the unit. I might wait a day or too and put some pics together and make a post outlineing my install. Yours looks great! How do you like it?
Thanks. I need to bleed my brakelines before I can say much about how much of an improvement it is. Though I know it is going to be tremendous.

My Jeep is a 71. But the write up should cover all FSJ's with a Duantless 350. My truck had three options from the factory, and power brakes wasn't one of them. I had read that the push rod stud was larger on Chevy's, but apparently that does not apply to 72 and older Jeeps. It looked like the Chevy stud was 1/2" and the Jeep's was 9/16". As for the spacer, Kaiser era rigs did not use one, unless you had Bendix power brakes, then a 1/2" or so thick plate was used. The push rod is only about 3" long on my truck, as the back side of the booster sticks in to the cab about 1" like it does on chevy trucks. Looking forward to your write up, the pics you posted in my first post looked really good.

[ January 12, 2006, 08:18 PM: Message edited by: KaiserMan ]
__________________
Thomas Russell
1975 Chevy K20 8400lb GVW Camper Special
1971 Gladiator
J2000 Platform-Stake Dump 350/T18

1970 Gladiator J3000 3407Z Camper Truck 350/T18
1963 Gladiator J300 Townside 350/TH400

Reply With Quote
  #6  
Old 01-13-2006, 12:52 AM
Elliott's Avatar
Elliott Elliott is offline
Cowboy Up
 
Join Date: Jun 22, 2002
Location: Pilot Point, TX
Posts: 12,704
Post

Nice write up! My adjustable rod ends and HB backing plate socket should be here any day now. I learned a lil more about the rod swaps also, Precision Rebuilders states that staked rods can be removed by annealing the staked area and then they have grommets and various length rods for replacement. I also read that trying to simply hammer that staked rod out can result in a cracked piston and that even pros have screwed up the rod swaps. I'll go the cut and thread option for my long rod. BTW I understand these units are rebuildable, but unless you have a removable rod or are able to aneal and remove it you can't replace the pistons seals during the rebuild. There really isn't much to the seal kit, I picked one up on E-bay cheapo.

Also, if you check out MPBrakes website they have a bunch of info on HP use in various rigs and there's some points they raise about different pedal lever rations between previously standard and power brakes that might involve some issues you should look at when doing this swap for older rigs. I'll look up the link I have somewhere...

[ January 13, 2006, 06:57 AM: Message edited by: Elliott ]
__________________
*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
Reply With Quote
  #7  
Old 01-13-2006, 01:08 AM
KaiserMan's Avatar
KaiserMan KaiserMan is offline
I got the Willys....
 
Join Date: Jun 21, 2005
Location: Huntington, Ma.
Posts: 8,692
Post

I cracked my HB apart and took a look at the push rod, and couldn't figure out how to remove it
Would you happen to know the torque specs for the bolts holding the HB case havles together?

A friend of mine rebuilt his hydro boost unit. He said it wasn't very hard, but I don't know exactly what was involved.

It sounds like MPBrakes website should be a good read. I'll have to check ot out later today.
__________________
Thomas Russell
1975 Chevy K20 8400lb GVW Camper Special
1971 Gladiator
J2000 Platform-Stake Dump 350/T18

1970 Gladiator J3000 3407Z Camper Truck 350/T18
1963 Gladiator J300 Townside 350/TH400

Reply With Quote
  #8  
Old 01-13-2006, 03:50 AM
Elliott's Avatar
Elliott Elliott is offline
Cowboy Up
 
Join Date: Jun 22, 2002
Location: Pilot Point, TX
Posts: 12,704
Post

I don't know about torque, but figure you could just use the torque specs for the size fastener if you can dig that up easier.

Page #45 in the pdf for ratios http://www.mpbrakes.com/catalog2003installpdf.htm
__________________
*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
Reply With Quote
  #9  
Old 01-13-2006, 03:35 PM
JeepsAndGuns's Avatar
JeepsAndGuns JeepsAndGuns is offline
AMC 4 OH! 1
 
Join Date: Jul 18, 2003
Location: Cullman, AL
Posts: 4,566
Post

I will try and work up my write up this weekend some time.

Quote:
Originally posted by Elliott:
Precision Rebuilders states that staked rods can be removed by annealing the staked area and then they have grommets and various length rods for replacement.
Only down side of that I see is the fact that heating it up enough to make it soft enough to pull the rod out will surly melt the seals on the inside of the unit. So replaceing those will be a must.
__________________
79 Cherokee Chief 401/T18/D20, MPFI fuel injection, hydroboost, otherwise stock.
Future mods: Caddy 500/NV4500/NP205, HP D60 front D60 smooth botom rear, 5.13 gears, 35x12.50's on H1 beadlock wheels. Warn M12000 winch.
93 Wrangler 4.6 stroker/AX15/NP231,SYE,CV, OME 2.5 lift, front hub conversion/big brakes, 31X10.50's Warn M10000 winch.
Reply With Quote
  #10  
Old 01-13-2006, 03:53 PM
Elliott's Avatar
Elliott Elliott is offline
Cowboy Up
 
Join Date: Jun 22, 2002
Location: Pilot Point, TX
Posts: 12,704
Post

Right, I got my rod ends today so I'll be threading my rod to be adjustable and be done with it. Not satisfied with this backing plate though, so I'm fiddling with issues around that.
__________________
*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
Reply With Quote
  #11  
Old 01-14-2006, 11:44 AM
Elliott's Avatar
Elliott Elliott is offline
Cowboy Up
 
Join Date: Jun 22, 2002
Location: Pilot Point, TX
Posts: 12,704
Post

Here's a link describing the effects of brake lever ratios: http://www.mpbrakes.com/manual.htm

I don't know if there actuall is any difference between the Kaiser manual ratio and AMC power ratio. Be interesting to know though. I tossed my old pedal assembly... let me know if you find a difference Thomas.
__________________
*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
Reply With Quote
  #12  
Old 01-14-2006, 03:39 PM
JeepsAndGuns's Avatar
JeepsAndGuns JeepsAndGuns is offline
AMC 4 OH! 1
 
Join Date: Jul 18, 2003
Location: Cullman, AL
Posts: 4,566
Post

Quote:
Originally posted by Elliott:
Here's a link describing the effects of brake lever ratios: http://www.mpbrakes.com/manual.htm

I don't know if there actuall is any difference between the Kaiser manual ratio and AMC power ratio. Be interesting to know though. I tossed my old pedal assembly... let me know if you find a difference Thomas.
Useing the formula on that page, and measureing the pedal assemble I have (79 with power brakes) I get aprox a 4.1 pedal raito.
__________________
79 Cherokee Chief 401/T18/D20, MPFI fuel injection, hydroboost, otherwise stock.
Future mods: Caddy 500/NV4500/NP205, HP D60 front D60 smooth botom rear, 5.13 gears, 35x12.50's on H1 beadlock wheels. Warn M12000 winch.
93 Wrangler 4.6 stroker/AX15/NP231,SYE,CV, OME 2.5 lift, front hub conversion/big brakes, 31X10.50's Warn M10000 winch.
Reply With Quote
  #13  
Old 01-16-2006, 02:48 AM
Elliott's Avatar
Elliott Elliott is offline
Cowboy Up
 
Join Date: Jun 22, 2002
Location: Pilot Point, TX
Posts: 12,704
Post

Here's info on bolt torque (from HydraTec) if you pull one of these apart to replace any seals:

"There are many variations in these assist units, to where some use 5/16-18 sized fasteners, while the newer units use a 10mm larger fastener. The earlier 5/16 sized fasteners need only 12-14 ft. lbs, while the newer/larger 10 mil fasteners require 22-24 ft. lbs."
__________________
*** I am collecting pics and info on any factory Jeep Dually trucks from the J-Series at the new Jeep Dually Registry.
***I can set you up with hydroboost for your brakes: http://www.ifsja.org/forums/vb/showthread.php?t=106056
Reply With Quote
  #14  
Old 06-05-2006, 06:44 PM
KaiserMan's Avatar
KaiserMan KaiserMan is offline
I got the Willys....
 
Join Date: Jun 21, 2005
Location: Huntington, Ma.
Posts: 8,692
Update!

After installing the hydro-boost in the above write up I found out it was bad. Luckily I had a spare HB that tested good. I didn’t want to have to take the spare HB to someone to have the push rod welded back together, so I decided to use a threaded on push rod eye. That was the goal I started with. What I ended up with is a way to mount a HB with out modifying the push rod length.




In order to mount the HB in without cutting the push rod I used a pair of 3" spacer brackets from a Bendix power brake system that I had pulled from my 67 Wagoneer. This setup was used on all Dauntless 350 powered Jeeps. I turned the brackets around, so the face that bolted to the firewall now bolts up to the HB backing plate. I also had to drill a new set of holes in the brackets in order to mount them to the firewall. In between the brackets and the firewall is a 3/8” spacer. I added this because with out it the pushrod bottomed out the brake pedal. In retrospect a ¼” spacer would have worked better, as the 3/8” spacer causes the brake pedal to sit slightly lower then the clutch pedal.



Spacer brackets with 3/8" spacer plate, stock cover plate (you can just see it in the bottom right hand corner) and a new viynl weather seal.


A differant angle of the same piece.



You can see that the brake pedal is just a little lower then the clutch pedal. This is with the 3/8" spacer.



The push rod lines up perfectly. The eye still needed to be opedn up to fit the Jeep stud.


In order to mount the HB to the spacer brackets I had to drill two holes in between the middle and lower mounting holes. The HB mounting plates middle holes line up with the spacer brackets lower holes. I have trimmed the HB plate for looks.




Everything al bolted back together. In this photo you can see just how much I have trimmed the HB mounting plate. The lower hols are stock, and the upper hols are the ones I had to drill.



A nice side shot. This assembly is LONG! The ratty looking thing between the spacer brackets and the HB plate are the original gaskets.



I had to clearance the heat tube to make room for the accumulator. I simply heated the tube up and beat it with a hammer until I had gained about ¼” of clearance. As you can see, the accumulator fits in nicely now.


Heat tube clearanced with a torch and a big hammer.


Accumulator fits in nice now. It was touching the heat tube before.


Everthing all done up (except one brake line that is to short).
__________________
Thomas Russell
1975 Chevy K20 8400lb GVW Camper Special
1971 Gladiator
J2000 Platform-Stake Dump 350/T18

1970 Gladiator J3000 3407Z Camper Truck 350/T18
1963 Gladiator J300 Townside 350/TH400

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:35 PM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
corner corner