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Improve Hydroboost Brakes

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
I have a GM Hydroboost and master from an 05' 2500 gas truck. I have a Kingpin 60 front with factory calipers and a 14 bolt rear with the Lugnut dana 44 brake kit. I installed a Wilwood prop valve for the rear. On a dirt road in 2wd i adjust prop valve to keep rear from locking up first. I'm a 5.3, 4L60, Atlas 5.0 and 4.56 gears. Brakes are not bad but do take some pretty good pressure when dropping off ledges. If I turn down the prop valve to improve rear brakes I can get them to drag just a little bit with no pressure on the pedal. I have the oem push rod which is 3.14". I have the PSC full hydro, CBR pump, big single ended ram, and I did go back and port the Hydroboost which dropped temps in the system but had no effect on steering or brakes. Per my temp stickers, I run 150 degrees pretty consistent. Have big cooler and fan. Steering is great, brakes are ok for a guy, bit much for a girl.

I'm trying to get a little less pressure on the pedal. My wife really enjoys driving the buggy but the pedal pressure is just a bit too much for her.

I'm wondering if pushrod length is wrong due to me getting a little brake drag? If i swap to the Dana 44 front calipers would this give me less effort?

Looking for direction on what I should check or change.

Thanks for your advise!!!
 

bgredjeep

Well-Known Member
Joined
Jul 1, 2011
Messages
704
I just took a quick look, and the most obvious thing I see is that the master cyl bore for the 05 Chevy is huge. I'm seeing ~1.45". For comparison, the 99 ram 2500 mc I'm using, which is pretty common for 1 ton setups, is 1.25".

If a hard pedal is the issue you want to address, I'd look into your options to swap a slightly smaller bore master.

Also, for your last question. I think swapping to smaller calipers in front would make the issue worse.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
I ordered the factory pedal from the same GM 2500 truck. I was trying to keep everything as correct as possible. I found online somewhere where they talked about pedal ratio. Manual vs vacuum vs hydroboost. I might be able to extend pedal a little, maybe an inch.

That is a good idea!! Thanks!!

I might swing by auto parts store and pick up a ram 2500 master and see how fitment looks. Looks like $100, cheap to try vs what I've spent on buggy.

That's another really good idea!!
 

JEEPKEVIN

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Joined
Jan 13, 2017
Messages
96
Thanks Zjman!! I work in an automotive shop and just clicked and ordered from my Oreilly's. They just dropped it off. The upside is if I don't like it they will take it back. Our shop is their biggest commercial account so they really like us. Now when I get to go home and see what I need to change. One port looks to be a different size so guess I will make one new line. Guess the old stuff can go into the spare parts bin for me or next dude that needs something.

Thanks for the input guys!! I'll report back.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
Won't be able to make it. I run a shop so I can get 3 day weekends here and there and really have to plan out my vacations. Thinking Hammers next year and wheel instead of work the race team. Depends what the wife has to say, considering how much she likes to drive the buggy, most of my time off will be wheeling.

I will be at Burrris/Rugged Mountain for the Tackett Creek Challenge Memorial weekend. Flex Rocks did that 24 hours from heck and back, the racers do the trail in 24 mins. AOP and Turtle were on my bucket list to wheel, great parks!! This place should be on yours if you get a chance. Crawlok.com has some info, follow them on facebook too.
 

ridered3

Not Rigless
Joined
Jun 24, 2010
Messages
7,236
Location
Rockvale, TN
Won't be able to make it. I run a shop so I can get 3 day weekends here and there and really have to plan out my vacations. Thinking Hammers next year and wheel instead of work the race team. Depends what the wife has to say, considering how much she likes to drive the buggy, most of my time off will be wheeling.

I will be at Burrris/Rugged Mountain for the Tackett Creek Challenge Memorial weekend. Flex Rocks did that 24 hours from heck and back, the racers do the trail in 24 mins. AOP and Turtle were on my bucket list to wheel, great parks!! This place should be on yours if you get a chance. Crawlok.com has some info, follow them on facebook too.
Understandable on being tied to work but awesome she wants to drive so more wheeling trips when time allows.

Burris/Rugged is on the list of places to checkout sometime. If you ever plan head East to Tennessee etc on one of your upcoming trips let me know and will try to meet up with y’all again.
 

paradisepwoffrd

Well-Known Member
Joined
Jun 5, 2012
Messages
1,161
Location
Hickory, NC
Another option to going with a smaller master, could be to go to a larger caliper/brake setup. But this might not work with current wheels, depending on the size youre running.
 

Lil ugly

Well-Known Member
Joined
Oct 6, 2011
Messages
753
Location
Jacksonville, Fl
I just fixed this issue on my truck. Switch your master to the 05 2500 one. Verify that it is the 1.25 version. It will greatly improve your brake pedal. The 3500 one is too large for the ford calipers.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
Thanks!!! I got a 1.25" bore one to swap out. We had storms last night so garage is full of everything I didn't want to blow away. Tonight is get garage back to my workspace so i can start teardown.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
After getting home and comparing, the GM master uses 1/2-20 ports for front and rear where the ram one had 2 different size metric ports. No big deal, I can get some fittings and brake lines. So I went back on Oreilys web site and the 05 Chevy half ton gas has the same 1/2-20 ports and a 1.25 bore. This will be a much easier bolt in swap. I have one of those headed to me. Interesting that the 05 half ton also has an option for hydroboost and that 1.46 bore too. We will see where this takes me.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
I'm here to confirm that the internet didn't lie. Brakes are noticeably better. I was a little concerned swapping stuff out that the pushrod was a little long but i think the hydroboost acts a little different. I had an oem pushrod which was 3.14" per all the googling i could do. Been that way for 2 years. I swapped out the the new master and had a hard time bleeding. I loosened the master and let it slide out 1/4" or so on the 2 mounting studs just in case it was not sitting in a netral position and not letting me draw fluid from the reservoir while bleeding. Didn't make any difference.

I was by myself so I vacuum bleed a whole quart through, then I made a 2x4 the right length to hold the pedal while I cracked my bleeders. That was the ticket. It now takes very little effort to hold the vehicle still in low range. It seems like there might be more pedal travel total but it takes less travel to do the job.
 

JEEPKEVIN

Well-Known Member
Joined
Jan 13, 2017
Messages
96
I started with the hydroboost and 1.46" bore master from a 05' 2500 burb with 8.1 gas and switched to an 05' 1500 Chevy 5.3 that did not have the hydroboost option. The specs said 1.25" bore.
 
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