NEWER HYDROBOOST? (1998-newer)

[Greg5OH]

pretty clear thanks Lcam. im going to see if the new SD hose threads into the old C2 pump..

 

[lindstromjd]

I am pretty sure lindstromjd has a newer hydroboost unit in his truck. He had to modify the length of the pushrod. And I think the bolt mounting holes are different. Maybe 3 instead of four.

That info is all truck info, e series I am not sure about.

Sounds like you might be on the right track!

Hi.
I do have a F-series SD style hydroboost on my truck. Came out of a 2003 with the 7.3, so I got lucky and grabbed everything associated with it. Booster, master cylinder, lines, hoses, pump, and engine mount. The engine mount did me no good, but I did get to sell it to a guy who needed one and ended up breaking even on the entire purchase, so no complaints there.

I did have to shorten my pushrod, because I didn't have the ability to build a custom bracket like I had hoped for to fit the 3-bolt style SD booster to the 4-bolt style OBS firewall. If I did it again, I would find someone who has the ability to machine a bracket and use it. When mounting the booster to the firewall, I just dropped it down a little so the pushrod was nice and level with the mounting tab on the brake pedal. No need to worry about the hydroboost specific pedal that way. For the lines, the SD style is a different thread pattern than the OBS truck steering box. The "cheap" way around this is use some compression fittings and cut off the ends of the SD lines, and the ends of your OBS lines, and then put them together with the compression fittings. I've done that three times now on different vehicles and never had a problem with them. It's also an easy way of making sure the parts are still available "off the shelf". Just takes a tube cutter and some wrenches to make it work. As far as the power steering pump, the SD style uses the exact same pump as the OBS, just with a different pulley. I pulled my old pulley off and used it on the new pump with not a single problem. I know that won't help you much with your v-belt set-up, but that's just what I did.

 

[LCAM-01XA]

Idk about compression fittings on the pressure line, there can over 1500psi in there sometimes, not something I'd be readily messing with considering it also powers the brakes booster. Kinda how in many states compression fittings are illegal for use on brake lines, only with somewhat lower pressures but applied over significantly larger area. I'd suggest double-flaring the two line pieces instead, that is a safer and OEM-used method of attaching things in the PS hydraulic circuit. JM2CW

 

[lindstromjd]

^^^ and that's why I mentioned that I've done it on 3 trucks now, and never once had an issue. The pressure line goes from the pump to the booster though, never touches anything else. It doesn't need spliced. Only the low pressure and return to and from the steering box need spliced.

 

[Greg5OH]

FYI 05 up uses a different pump than OBS and pre 04 trucks.

 

[laserjock]

For what it's worth, if you guys get into a spot, there is nothing wrong with using the "correct" compression fittings on high pressure hydraulic lines.

www.swagelok.com

These guys will have you covered for about anything. Not cheap but ultra-reliable. They have really good tech sheets so you can figure out what you need for your application. I have bought thousands and of dollars worth of fittings for my day job and never a problem. They are good for other things too like fuel, water and oil lines etc. Brass fittings intended for domestic water are probably not the best idea.

 

[LCAM-01XA]

^^^ and that's why I mentioned that I've done it on 3 trucks now, and never once had an issue. The pressure line goes from the pump to the booster though, never touches anything else. It doesn't need spliced

Yeah I get that, done some such shenanigans myself too But, you know, CYA and all that...

. Only the low pressure and return to and from the steering box need spliced.

Actually just to clear up a possible misconception, the line running from the hydro down to the steering box is NOT a low-pressure line at all. Unless you are on the brakes it handles the exact same pressure and flow that the main feed from the pump to the booster does, in other words the hydro is in full pass-thru mode and effectively acts like nothing more than a giant funky-looking union fitting. Then when you get on the brakes the spool valve in the hydro restricts flow to the steering box, but the pressure is still mostly there as the steering box relies on pressure and not so much on flow. That's why people usually don't have issues steering while braking till they throw a ram-assist cylinder on - now that thing needs not just pressure but also flow, and flow thru the steering is something that typically lacks while the hydroboost is doing its thing. There is a work-around, but that's beyond the scope of this discussion now

 

[SDEconVan]

Lots of good stuff coming up on this thread!!

Focusing back onto the original effort, to convert my 1985 6.9L idi Club Wagon van using a 1998-newer Hydro Boost,

I continued on my fact-finding:

I got a hold of a HydroBoost unit with the master cylinder,

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2006 E450 ('04-'07 year range)

Why that year range? I already purchased from the guy who was parting it out. Also, they are plentiful and most
seem in pretty good shape. If I got a 1992 one for example I would rebuild for sure (still will inspect this one.)

See that triple bracket piece, it's kind of useless for my application even though it looks nifty. It is a pretty tight
fit in the vans. The angled fittings I think are going to mess me up, right now I am thinking I don't want to adapt
onto those. (I am interested in the fitting (thread and type) at the actual HydroBoost unit.)

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Here is a better view of the relevant fitting type, entering the top of the black HB unit.

The reservoir is HUGE by the way...

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One thing I didn't consider til now was the electrical connections. One is the brake light, I should be able to adapt either
by change-out of the sensor or adapting the 2 vehicle wires to the 2006 connector. The other connection is for
Low Fluid warning. My 1985 does not have this as far as I know (I have not driven my van yet, so haven't really
"discovered" all the running light up details of it.)

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The unit came with the Link to the Brake Pedal Arm. Note also the bolt pattern is the same as 1985, though I will
be modifying it a bit.

More fact finding:

Checking out the Power Steer Gear in my 1985 Diesel,

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I am still in the process of ID'ing the flare nut size and connection type. (Mid 80's was a time of lots of metric stuff
going on in the US, I just got out of Eng School and they trained us on the metric system, yet the "real world" then
was most all Standard, and we didn't know which one would take over- so we used both... ARRRGH.)

My thought right now is, "Old steer gear company, STANDARD Flare Nut size..." but they would build to spec, so...

This is the Saginaw Pump in my 1985 Diesel,

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Called "Canned Ham" because of tank shape, that's a small ham. The Saginaw was prevalent in GM products, same
basic shape but probably many different capacities due to requirements of the contractors.

View from underneath, Steer Gear to the left,

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Looking closely, there is the existing Return line (center of can.) Since it has lower line pressure (IN) it can be a
friction-fit connection with a hose clamp if needed. Note the other connection is the higher pressure line (OUT,)
which is silver in color, and is a hard line out, having a threaded fitting. Right now, I think this fitting is 16mm
based upon the specs of the available replacement hoses (it is listed as "16mm" on parts searches.)

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The high pressure line will be re-routed to HydroBoost (IN) which I hope to swap out the 2006 Flare Nut on the line and
install it using my Flaring Tool. If not, I will either use an adapter (at either end,) or have a hose made.

There will be a SECOND high pressure line. This is a new addition to the system, and it will run from the HB (OUT)
down to the Power Steer Gear. Schematically,

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Now in the vans, the proximity of the Pump/HydroBoost/Steer Gear is pretty close. (The Brake Master is practically
straight above the Steer Gear, with the Pump in-between the two.)

Based upon the schematic, my easiest approach will be to use the 1985 OEM line (Line 1,) try to swap to a
2006 flare nut, at the HydroBoost end, and do a double flare. The other end, at the Canned Ham will be a direct bolt on.

In a perfect world, I am thinking of getting a second identical line, (1985 OEM,) (Line 2,) and trying to swap the flare nut
at the HydroBoost end. The Steer Gear end will be a direct bolt on. *still figuring the needed hose length, about 20 inches
for the OEM Van hose, there are longer ones used (with the same ends,) used in the trucks.

Lines 3 and 4 show the Return Circuit. Still figuring this, someplace someone said they had trouble with overflow/choke at
the T-fitting. Right now, I have to call ******** on this one, since no extra fluid is being introduced to the circuit- still, I do
not know the "back flow" behavior, or if the HB "stores" fluid then lets a burst of fluid out (while at the same time the Steer
Gear pumps it's largest amount.) Conflict? Not sure. Could happen but it seems simpler than that, perhaps the T-Fitting is
okay.

Otherwise I will braze another fitting onto the back of the Ham Can...

If anyone can absolutely tell me for sure that the flare nuts at the HydroBoost cannot be swapped out, please chime in (Flame
Suit On!)

Best regards,
George

 

[LCAM-01XA]

See that triple bracket piece, it's kind of useless for my application even though it looks nifty. It is a pretty tight
fit in the vans. The angled fittings I think are going to mess me up, right now I am thinking I don't want to adapt
onto those. (I am interested in the fitting (thread and type) at the actual HydroBoost unit.)

Should be metric, IIRC 18mm o-ring on both pressure ports.

One thing I didn't consider til now was the electrical connections. One is the brake light, I should be able to adapt either
by change-out of the sensor or adapting the 2 vehicle wires to the 2006 connector. The other connection is for
Low Fluid warning. My 1985 does not have this as far as I know (I have not driven my van yet, so haven't really
"discovered" all the running light up details of it.)

You don't need any of those connectors. The one the bottom of the master is not for the brake lights but for the cruise control, it works off brake fluid pressure and is used to momentarily disengage the cruise while your are on the brakes. The cruise control in your van uses a vacuum-modulated servo system, and as such it has a mechanical vacuum dump switch under the dash - when the pedal moves away from its "idle" position the valve opens and purges all vacuum from the servo and thus stops it from pulling (via a cable) on the throttle lever on your injection pump. The brake lights in your van are powered via an electrical switch that rides on your brake pedal, on the same pivot used for connecting the brake booster to it actually. You should be able to keep this factory setup fairly easy, I wouldn't try re-purposing the pressure switch on the new master cylinder to power the brake lights as that may be more current draw than the switch was designed for - but with LED lights in the rear that issue could possibly be solved.

The switch on the reservoir is, like you said, for the low brake fluid warning, which in your van does not exist. You can add your own warning light if you want to, personally I'd be very tempted to do so

My thought right now is, "Old steer gear company, STANDARD Flare Nut size..." but they would build to spec, so...

That would be correct - 5/16" SAE flare (your regular double-flare for 5/16" fuel line) for the pressure line going in, same type of connection but in 3/8" for the return going out.

Looking closely, there is the existing Return line (center of can.) Since it has lower line pressure (IN) it can be a
friction-fit connection with a hose clamp if needed. Note the other connection is the higher pressure line (OUT,)
which is silver in color, and is a hard line out, having a threaded fitting. Right now, I think this fitting is 16mm
based upon the specs of the available replacement hoses (it is listed as "16mm" on parts searches.)

16mm is correct for the '85, but keep in mind it's a special o-ring fitting that you won't be able to easily duplicate.

Based upon the schematic, my easiest approach will be to use the 1985 OEM line (Line 1,) try to swap to a
2006 flare nut, at the HydroBoost end, and do a double flare. The other end, at the Canned Ham will be a direct bolt on.

In a perfect world, I am thinking of getting a second identical line, (1985 OEM,) (Line 2,) and trying to swap the flare nut
at the HydroBoost end. The Steer Gear end will be a direct bolt on. *still figuring the needed hose length, about 20 inches
for the OEM Van hose, there are longer ones used (with the same ends,) used in the trucks.

As long as the factory '85 E-series pressure lines are of the same diameter as the 2006 hydroboost ones, that could work. IIRC the '85 line is 3/8" on the pump end so that should match the '06 hydroboost outbound (to the steering box) line piece. You have a problem with the line between the pump and the hydro tho, obviously it will bolt up to the pump just fine but its other end has 5/16" line, which won't match directly to the '06 inbound line piece if said piece is also 3/8" - thankfully they do make all sorts of SAE flare adapters, you may be able to find a suitable 3/8"-5/16" piece that takes care of the size mismatch.

I donot know the "back flow" behavior, or if the HB "stores" fluid then lets a burst of fluid out (while at the same time the Steer
Gear pumps it's largest amount).

That is exactly what it does. The T-ee fitting is a hit or miss, we've seen a few trucks done like that and having no issues whatsoever, while some people report problems. Could possibly be based on the pump's flow rates, not all pumps are the same. If possible avoiding the T-ee fitting would be to shoot for, it's really not worth taking a chance there.

Otherwise I will braze another fitting onto the back of the Ham Can...

Or go grab a reservoir off some '80s GM hydroboosted truck - it's basically the same reservoir as yours, only it has the two return ports you need. Also IIRC there are several different configurations to choose from as far as positioning and orientation of said ports, which with a van that's so tight for space may make your work a bit easier...

If anyone can absolutely tell me for sure that the flare nuts at the HydroBoost cannot be swapped out, please chime in (Flame
Suit On!)

Which nuts? There is no functional downside to removing those short factory line pieces and replacing them with whatever else fits your needs and space availability. Pretty much as long as what you do threads in and doesn't leak, you're good to go.