GM hydro boost brakes for newbies like me....

[chilliwak]

There's a 3rd option as well, at least as far as the PS pump is concerned. The fitting that the pressure hose threads into can be removed and swapped from one style to the other. On our FrankenFord we are running a Saginaw PS pump, for a while we used the metric fitting and a late-'90s GM 3500 pressure hose attached to it, then later we switched to the '70s double-flare setup with a different hose as that gave us better clearances around the other engine accessories. Pump even remained bolted to the engine the whole time, we just unscrewed one fitting and screwed the other one it its place. Most of the fluid leaked out in the process, and one also needs to be aware that inside the pump behind said fitting there is a spring-loaded valve, it won't try to fly out and kill you or anything but it's still a good idea to remove the fitting slowly.

Under drive is there any info as to supplier of the fittings you mentioned so that I can run an old 1979 steering box and power steering pump with the brake fluid housing and pedal set-up with metric hoses from a 85 cucv Blazer truck?

 

[Larry]

Thank you for that super cool and detailed parts write up Larry. Are the old sae hoses for the 1979 and previous C30 trucks with hydro boost not available anymore? I was thinking that I could order an old school 1979 brake fluid housing that had sae thread and then get the hoses that fit so that I could run my existing power steering pump and steering box. Please let me know...:ylsmoke:

Yes, the older hydroboost lines are still available for the standard thread hydroboosters. So is the booster itself (Napa pn 529393) but it does not come with the booster to firewall bracket or push rod as I mentioned in other threads on this topic. I`m not following the rest of your question though??? Brake fluid housing?? What are you talking about dude? That would be the master cylinder and you don’t need to worry about the brake line threads in the m/c…they will be the same regardless (SAE ½ and 9/16). Actually, you might be able to get away with using your m/c if you wanted. Keep in mind, the hydrobooster runs on power steering fluid while the master cylinder runs on brake fluid. The two fluids do not mix anywhere in the system.

Back to where we began with this topic in the other thread….. Your truck has standard thread p/s pump and steering gear. A donor hydrobooster will most likely be metric unless you can find a 1979 or older truck to pirate the booster from, which will be unlikely.

So, here are the options again, assuming you will use a ’80 and later metric thread hydrobooster…..

1) Have a custom set of hoses made by a hydraulic shop so you can have standard thread at the p/s pump and steering gear and metric at the booster. That is how my K10 is and it worries me because if I have a hose problem out on a trip I won’t be able to just walk in buy an off the shelf hose.

2) Build your own lines out of AN stuff with the correct fittings (might just be the best option for you)

3) Replace the pump and steering gear with later units with metric threads. As mentioned, above you could potentially replace the pressure valve in existing pump with one from a newer pump with metric threads. Although I have found the pressure relief valve has different threads in the external body of it where it won’t screw into an older pump. I just tried to do that same thing for my buddy Rob with his Gen III LS K5 Blazer engine project by taking bits and pieces of different p/s pumps (metric and SAE) to build one usable one. Didn’t work, not on the concoction we tried to build anyway, but there very well could be a pressure valve in existence with standard threads on the pressure valve body and metric in the hose fitting.

 

[Ridge Runner]

Larry, what about chilli keeping his PS pump and box, cutting the flare off of one end of the hydroboost lines, sticking his standard nut on there, and re-flaring the fitting?

 

[Larry]

That is basically what I am talking about when I mentioned have a set of custom hoses made. Someone could do that at home if they have the flaring tools, etc. The flaring tools I had were not strong enough to flare the metal portion of the hoses after sliding on a SAE tube nut which is why I had to have a hydraulic shop rework them for me. It could be done though

 

[Ridge Runner]

Roger that. Looking at the lines, that's what I suggested to chilli that he do the other day. Like you said, as long as one has a good flaring tool, I think this would be easy to do.

 

[chilliwak]

Thank you everyone, I might actually be starting to grasp this project now. Larry I did mean the master cylinder; I guess my English is getting really rusty living in Europe. It does seem that the easiest thing is to get some hoses made but I am wondering about the cost. The easiest thing would just replace the whole system but that might be a huge expense. Larry your friend Aaron can get me a whole pedal system with master cylinder out of a Blazer Cucv. With that in mind I could (A) buy a master cylinder with sae fittings, new hoses(sae) and install that, if the push rod and pedal system from the 85 Blazer Cucv would work with the older style master cylinder. Or (B) install new hoses that are metric and then get fittings that convert the hoses to sae at both the pump and the steering box. Or (C) get special hoses that have metric at one end and sae at the pump and steering box side so that the whole system can be tied together. Something tells me that I should probably replace as much of the components as possible as my truck is a 1979. Just wondering what a power steering pump and steering box would end up costing me.Please comment as to the easiest and most cost effective method. Cheers, Chilli...:ylsmoke:

 

[underdrive]

Under drive is there any info as to supplier of the fittings you mentioned so that I can run an old 1979 steering box and power steering pump with the brake fluid housing and pedal set-up with metric hoses from a 85 cucv Blazer truck?

The fitting on the back of the pump would be a junkyard item, I believe ours came out of a big '70s Lincoln, mostly cause that was the first hydroboosted vehicle we ran into that day that had the SAE flare connection and that the pump was stupid-easy to get to. However Larry may be on to something there - I honestly don't know why the fittings swap worked for us but not for him and his friend's truck, I know the fitting we took out was the typical metric o-ring setup and the Lincoln SAE flare fitting threaded right in its place. We didn't mess with the valve behind the fitting, that remained in the pump, we only swapped the fitting that holds it in place while also retaining the reservoir and hooking up to the pressure hose...

Unfortunately when it comes to the steering box I have no solution to adapting the metric o-ring end of the CUCV hose to the SAE flare on your box. Well, there is one solution, and it is what RidgeRunner suggested - cut the metric end off the CUCV hose, and double-flare for SAE flared ports. This is what we did on our old truck, it was a '78 Chevy with I believe '86 hydroboost - that one didn't get the fitting swapped, we just modified both hoses. And yes Larry is right that it's a bear to get a proper double-flare on the 3/8" steel tube, we ended up having to put the clamping bar of the flare tool in a vice and crank that tight so that the bar finally has sufficient force to hold the tube from sliding back whenever the die started pressing against it.

 

[SlowJoe]

You could cut the end off of both hoses and reconnect the standard flare fitting onto the new hose using a swagelok connector:

http://www.swagelok.com/search/find...0-6&item=20b6dcb5-5a04-42f1-9df7-a5d3fd3672c3

The link is for a 3/8 to 3/8, but if the tube is actually 8mm or some other size, they offer them as well. They have all sorts of connectors and certainly something should make it all work for you. Or, you could just order a kit from Vanco and bolt it on, so you do not have to worry about any of those issues at all.....

:26_7_2:

 

[underdrive]

You could cut the end off of both hoses and reconnect the standard flare fitting onto the new hose using a swagelok connector:
http://www.swagelok.com/search/find...0-6&item=20b6dcb5-5a04-42f1-9df7-a5d3fd3672c3

Joe, that's what's commonly known as a compression union, it has no place in high-pressure automotive hydraulic systems. The SAE flare and the metric O-ring both retain the hose end to the pump or steering box mechanically, short of the nut backing out there connection won't let go. On the other hand the compression fittings rely on just friction between the ferrules and the steel lines to keep things together, we've been told that good-quality compression fittings (such as those made by Swagelok) when properly installed can hold up to pressures in the order of thousands of psi, however unless they do such installs day in and day out how can one be 100% certain they installed their fitting correctly?

Additionally many locales have annual vehicle inspections, and in many of the rulebooks those are governed by compression fittings and unions are banned from use in high-pressure systems (brakes and power steering usually, possibly some fuel systems as well). Therefore if an inspections technician in such a locale runs into compression unions they have the right to fail the vehicle on the spot even if all else checks out.

 

[chilliwak]

Does anybody know if the pedal and rod assembly off a 85 Blazer Cucv with metric hoses can be used to adapt a master cylinder from a 1979 or previous C30? It seems to me the easiest way would be to use the pedal, piston, and rod assembly off the 85 Blazer cucv, then buy a new master cylinder that is from a 1979 or previous C30 pick-up and then just getting new sae hoses that fit or work with my existing 1979 C10 power steering pump and steering box. What do you guys think?:wings:

 

[Larry]

Does anybody know if the pedal and rod assembly off a 85 Blazer Cucv with metric hoses can be used to adapt a master cylinder from a 1979 or previous C30? It seems to me the easiest way would be to use the pedal, piston, and rod assembly off the 85 Blazer cucv, then buy a new master cylinder that is from a 1979 or previous C30 pick-up and then just getting new sae hoses that fit or work with my existing 1979 C10 power steering pump and steering box. What do you guys think?:wings:

YES! Like I said above in post 47, don’t worry about the master cylinder as the brake lines that thread into it will be standard thread regardless if the master cylinder came from a ’80..’90…’95…98 or whatever. Master cylinders themselves did not change to metric threads where the brake lines thread into it until around model year 2001ish. You could use a 1984 C/K 30 master cylinder but you will probably have to swap the lines around from front to back, which may get confusing or just use an 84 K4 6.2L diesel spec master cylinder (recommended)….or in your case, it would probably be easier to just reuse your existing master cylinder that way you don’t have to crack open any lines then have bleed the brakes afterwards. My preference is to use whatever master cylinder part number matches the donor truck the hybrobooster came from...which would be an '84 K5 diesel Blazer in this case.

 

[underdrive]

Chili, like Larry said it's the hydroboost unit itself that requires the hoses swap, not the master cylinder. Master cylinder can simply be unbolted from your current vacuum booster and left kinda hanging by the brake lines (support it with a bungee cord coming down from the hood though, thing is pretty heavy) while you pull the vacuum booster out and drop the hydroboost in. Well, and do the pedal work as well. But yeah, point is, if you're stuck using CUCV hydroboost you'll be dealing with its metric ports. Price a hose hit from Vanco though, they seem to have a good handle on what fittings are needed for both SAE and metric ports. And seeing how what they got is essentially AN-ended hoses with just adapter fittings, once you get their kit should a hose let go on you a replacement could be made at any big-truck service center or a hydraulics shop - the end fittings are non-wear items and when replacing hoses you leave them attached to the pump and box and hydro unit, you can change hoses all you want and they will always seal properly.

 

[chilliwak]

Is there not just a off the shelf hydro boost housing from some aftermarket dealer that works with off the shelf sae hydraulic lines that can be readily bought at some parts store? It sure would make the whole thing a hell of a lot easier.:Wow1:

 

[SlowJoe]

Joe, that's what's commonly known as a compression union, it has no place in high-pressure automotive hydraulic systems. The SAE flare and the metric O-ring both retain the hose end to the pump or steering box mechanically, short of the nut backing out there connection won't let go. On the other hand the compression fittings rely on just friction between the ferrules and the steel lines to keep things together, we've been told that good-quality compression fittings (such as those made by Swagelok) when properly installed can hold up to pressures in the order of thousands of psi, however unless they do such installs day in and day out how can one be 100% certain they installed their fitting correctly?

Additionally many locales have annual vehicle inspections, and in many of the rulebooks those are governed by compression fittings and unions are banned from use in high-pressure systems (brakes and power steering usually, possibly some fuel systems as well). Therefore if an inspections technician in such a locale runs into compression unions they have the right to fail the vehicle on the spot even if all else checks out.

I am familiar with all sorts of compression fittings and Swagelox fittings are not the typical hardware store garbage fittings that you correctly state have no place on a vehicle. When using a Swagelok fitting, the tubing itself is the weak link, not the fittings. They can withstand any pressure the tubing being used can, and are regularly tested to pressures well over 10K psi. I use them every day and they will without question stand up to the 1500psi or less that these pumps put out and are actually stronger than any other OEM fitting you could find on the vehicle. Here is a video showing some of the destructive testing the company does:

https://www.youtube.com/watch?v=lc4Yx_Uylfo

So far as the correct installation goes for them, they are to be tightened 1&1/4 turns to swage the ferule onto the tube and provide the mechanical connection. One reason we use them so often ( I work at a University) is because they are nearly idiot proof and the inexperienced students can (almost) always get them tightened successfully without leaks. Once tightened they are permanent and as seen in the video above, can not be pulled free. Everyone has to work within their own comfort limits though, so if someone is not comfortable with such a fitting they should not use it, and would need to convert it to AN, flare or whatever else was available and acceptable to the application. Thank you for helping to point out these differences because I certainly would not want to give someone the impression that they could pop into Lowe's to pick up a normal compression fitting and use it successfully!

 

[SlowJoe]

Is there not just a off the shelf hydro boost housing from some aftermarket dealer that works with off the shelf sae hydraulic lines that can be readily bought at some parts store? It sure would make the whole thing a hell of a lot easier.:Wow1:

Hi Chilli,

I posted the link about the Vanco system. That is an "off the shelf" system that you can bolt onto your truck. There is no engineering or creativity necessary on the part of the installer except for the few things I mentioned. I am certainly capable of cobbling together the parts to make a system from scratch, but I did not have the time to do it because I am in the middle of a house renovation project that is consuming nearly every minute of my time away from my job. I just needed brakes on my truck, and I needed them now. The Vanco system is a good option for that, and with the system comes the technical support and knowledge he can offer you if you need assistance. Other options have been posted that are just as good by others here, but may take a bit more engineering creativity or time on your part. All options have their pro's and con's but you will need to decide what option is best for you. The Vanco option is a bit more with the upfront cost, but is a great time saver and you can bolt it on without solving plumbing connection issues. If you need to pinch pennies, then you may be better off hunting the bits you need from junkyards and/ or ebay. However, you will risk getting parts that may be of uncertain condition and need to be rebuilt, or may have fitment issues. It seems that you have asked several questions multiple times but even though you have received the answers, you continue to ask them again. I mentioned how the brake pedal issue could be addressed by using your own pedal, but you asked multiple times about it after my post. Maybe you don't believe me, but if you looked under your dashboard at your brake pedal, you could verify what I stated to be the truth. I am not trying to be a jerk, but there have been more than adequate answers to all of your questions from multiple people. If you are not comfortable doing the swap with salvaged parts even with all of the details provided by others, I respectfully suggest that path may not be the best for you. The Vanco unit removes all issues for you in one happy box that arrives on your front door step. I would be happy to talk to you on the phone about my swap or send photos that may be helpful. Good luck with whatever path you choose and please let me know if/ how I can help.