Hydro-boost questions (looking for data)

[70chall440]

I will be carefully watching your progress. I have had HB in pickups and liked the system. Had a friend running it in a Chevelle with no issues. Doesn't seem like it should be tough to get it to work in a Mopar, but it doesn't seem to have much of a following among Mopar owners. In the meantime, I will be cleaning up this beast while I am cleaning other parts...View attachment 1418389
If nothing else, I know the pump was working with the HB, and that it was bolted to a 440. May not be much else that is relevant or useful since it was all on a Winnebago.

I will try and post information as I come onto it. I am pretty sure that I will be able to get the 85 D150 MC to fit onto the HB system. I spent some time researching all of the fittings and ended up ordering some so that I can make up some -6 AN lines. There seems to be some differing information about the hoses, however I think I will use braided PTFE lines.

I am not sure why these are not attractive to Mopar guys, perhaps its the ascetics as they don't look all that great.

 

[64fury74charger]

I like the compact setup of the hb unit. Certainly takes up less space than a vacuum booster and with a little paint it can blend in. I am going to see if I can find some information on how the pressure is regulated and maybe find out information on the amount of boost in relation to vehicle size and/or gcvw.

 

[64fury74charger]

You may already have this info but I found hydratechbraking.com and browsing through I didn’t see any specific info on the booster in relation to car type or size. Maybe the booster assist is not so much of an issue as having the proper pressure from the pump and making sure the fluid stays relatively cool. Your thoughts?
I am known to over think things sometimes. Lol

 

[70chall440]

You may already have this info but I found hydratechbraking.com and browsing through I didn’t see any specific info on the booster in relation to car type or size. Maybe the booster assist is not so much of an issue as having the proper pressure from the pump and making sure the fluid stays relatively cool. Your thoughts?
I am known to over think things sometimes. Lol

LOL yeah I have been known to overthink things as well from time to time.

I had not seen that link, thanks.

I really do not know what the difference would be between a HB unit in say a 1 ton truck and one in an Astro van (or similar passenger car). Thinking it through my "gut" says that the differences lie more with the overall system rather than just the HB unit (PS pump, steering box, caliper or brake cylinder bore size, rotor and/or drum size, pad/shoe size and material, etc. There could be a difference in valving I suppose.

I am sure someone will pop up and provide some information but this is where I am now.

 

[Kern Dog]

I am not sure why these are not attractive to Mopar guys, perhaps its the appearance as they don't look all that great.

I was okay with the appearance of it.

If I had some tech support, I'd gladly try this again. I just feel burned by my previous attempt. I had almost no help at all and answers were hard to come by.

 

[70chall440]

@64fury74charger I am looking at that link you sent me and I realize I have been there before. These guys are using rebuilt units I think, same as anyone else can buy

 

[70chall440]

I was okay with the appearance of it.

View attachment 1418761

View attachment 1418762

If I had some tech support, I'd gladly try this again. I just feel burned by my previous attempt. I had almost no help at all and answers were hard to come by.

Yeah I don't mind how they look either but I have seen posts by others hating on them. I think I am going to mount mine with the accumulator on the outboard side. This will put the lines on the bottom and I think make for a cleaner install.

I know what you mean about the no support thing, it definitely sucks. I predominately work alone but I have a very well equipped shop (better than most professional shops). I like tools and buy about anything that might make my life easier.

 

[64fury74charger]

My thinking is looking at the particular master cylinder being matched correctly with the calipers because that is where I have seen the most issues. And then a properly adjusted rear proportioning valve to balance the system.

I think at this point I am not too concerned about the booster itself as long as it gets proper and consistent pressure. The master cylinder is the key I think. Wow this takes a load off my mind. Thoughts?

 

[64fury74charger]

@64fury74charger I am looking at that link you sent me and I realize I have been there before. These guys are using rebuilt units I think, same as anyone else can buy

I figured you already had been there, I was searching for info and that came up so I poked around. I wouldn’t buy an aftermarket kit anyway because I like the challenges and save some money and do things the way I want and learn along the way.

 

[70chall440]

Well my thoughts are that in a HB system the MC is not nearly as critical as it is in a standard manual or vacuum boosted application. This is due to the increased pressure that the HB provides which is significantly more than the other systems.

I do agree that the system needs to be balanced or proportioned if you will correctly.

 

[Kern Dog]

My efforts included a Dr Diff prototype HB unit. He suggested that I use a Raybestos master cylinder with a 1 1/8" bore.

RAYBESTOS MC39178 Specifications
Number of Ports	2
Primary Port Thread A	1/2"-20
Secondary Port Thread A	9/16"-20

 

[70chall440]

Yeah that is what I have which as I mentioned does not exactly match the bolt distance on the HB unit but it isn't a deal breaker.

 

[70chall440]

My efforts included a Dr Diff prototype HB unit. He suggested that I use a Raybestos master cylinder with a 1 1/8" bore.

RAYBESTOS MC39178 Specifications
Number of Ports	2
Primary Port Thread A	1/2"-20
Secondary Port Thread A	9/16"-20

Did Cass mention what HB unit he (you) were using?

 

[fesser]

I was okay with the appearance of it.

View attachment 1418761

View attachment 1418762

If I had some tech support, I'd gladly try this again. I just feel burned by my previous attempt. I had almost no help at all and answers were hard to come by.

I think your setup looked great. The information about fittings and hoses was extremely valuable. Even though it didn't work out for you, you laid down some foundation that those that follow won't have to figure out the hard way.

 

[70chall440]

So I have been doing some research and I came across an individual selling HB systems on eBay, subsequently I asked him some questions (such as we have been discussing here) he was very knowledgeable and responded articulately. For the betterment of those following, here are the questions and his answers;

 

[70chall440]

Question: is a Ram 3500 HB a GM unit?

Answer: It's a Bosch patent and there are slight differences but the units are the same essentially.

Question: What are the differences between most HB units?

Answer: There are variances, some in the rotation used, type of MC that fits, length of MC input rod, size of the input spring retainer, size of the opening in the front of the booster, size of the piston inside the booster, the dimple depth in the piston inside the booster, size of the seals required, different diameters of the staked section of the rod, type of brake rod used, type of linkage used on the piston assembly, some had pressure relief fittings, length of the accumulator used and the level of nitrogen charge in the accumulator, type of pressure ports and what fits them, ID of the pressure ports, if a manifold was used, ect. So, yes there are a number of differences.

Question: Are most HB units the same in terms of output pressure?

Answer: There are differences in what some units put out and there are differences in what PSI and GPM rate they operate best at. The astro is essentially the same as the one ton but you can alter line pressure with the bore size of the MC and size of the lines feeding them. The Mustang units are a bit of an oddball for a number of reasons. I've never tested line pressure with them but doubt it's as high as the one tons as the power piston is smaller. If they did put out as much pressure then Ford would have just used their one ton booster. Oh, there are some early units that didn't have an accumulator and then some that had an accumulator with a spring inside instead of nitrogen... those were early Bendix units.

 

[64fury74charger]

Interesting points about the pressure difference and how the potential output is varied depending on the internal parts and of course the line pressure going in. Thank you for posting this. Answers some questions.

 

[70chall440]

I also asked about other HB units and the stud spacing for the master cylinders. Mopar MC spacing is ~3.2" (I measured 3.151 on mine) however Mopar HB units have a 3.4" spacing (basically .25" difference between them). There is a company called Hydratech who is selling a system wherein the MC bolts right up to the HB unit so I was wondering if there was a HB unit out there with a 3.2" spacing and I asked the guy on eBay, here is his response;

The Mopar hydroboost had 3.4" bolt spacing from '98+ so my guess is they are slotting the holes on the MC flange to accommodate that.

 

[70chall440]

For those wanting to go down the HB path but don't want to do it like I am (the Johnny Cash method, 1 part at a time) and don't have to ability to fabricate and don't want to drop $1000+ on a kit, I recommend you check out this link

https://www.ebay.com/ulk/usr/sterlingworth16?mkevt=1&mkpid=0&emsid=e12052.m44.l1181&mkcid=7&ch=osgood&euid=78844fbba37840638029f3a0e668cbb9&bu=43179920711&osub=-1~1&crd=20230216180737&segname=12052

This is the guy who I have been talking to, he offers HB units for Mopars, you will still need to source lines and the various connectors (depending on how you want to connect it up) and how you want to connect the PS pump.

 

[64fury74charger]

I think this whole process is moving in the right direction and would be doable for well under $1000.00. You have really helped take some of the mystery out of the booster set up. Thank you for your time and effort to post your information here for anyone else who wants to upgrade their brakes.