power steerin question.

[engineeradam]

Three things.
1. Does anybody have a rebuild guide for a steering gearbox? Is it hard to do? And where would you get a kit?
2. If i apply my brakes the steering gets real stiff. I already flushed the hydro boost once, should i do more?
3. I got a gas tank of a gas truck and it has three lines out of it. What the third? and is there any way to rig the feed from two tanks to suck evenly to eliminate the need for a selector valve

FYI its a 1987 GMC sierra 1500 6.2L

[john8662]

I wouldn't suspect the gearbox itself, but maybe the powersteering pump. The powersteering pump is what provides the hydraulic pressure used for both the steering and the power brakes via hydroboost.

Be careful using a tanke from a gas truck. The first problem (besides the ones you've noted) is that the filler neck is going to be smaller for the gas trucks than the one for the Diesel. The connection on the tank is smaller. So your hose and what not won't connect to the tank.

A lot of the early Diesel 82's for sure had three connections up top. One went to a fuel "T" I think it was used for purging the system of water somehow. Never used it, both my 82's have them.

[engineeradam]

i know its the hydroboost and not the pump or gearbox. I just want to rebuild an old gearbox i have because it leaks. So can i cap one of the three lines? I know the big one 3/8" is the feed, which of the 5/16 is the purge and the return?

[engineeradam]

Wheres DMAX. he really knows his stuff.

[Robyn]

Gettin a "KIT" for a steering box is in about the same catagory as getting a kit for the Hydrobooster, Tough to find.

GM used to sell the kits through their parts dept. Generally these parts are available from the rebuilders but most parts houses will come up short.

The tank issue is not a Biggy. You can remove the little bulkhead with the flapper in the filler neck with a hole saw.

Just place the diesel stickers in the filler door to mark that its a diesel.

Use the feed line and the vent line.

Now to set up a dual draw dual return is not really easy, and requires some valves.

Best to use a switch valve that will switch the draw line and the return line at the same time. Keep it simple.

The factory electric tank valves were at times unreliable after they got time on them.

The sending units are different between gas an diesel as the float on the sender is different due to the specific gravity of the fuels ??

At least this is what I have been led to believe. The senders are a different part number.

It will work though either way. Just check your gauge with any given amount of fuel to test accuracy.

OOOOOK

Went to LMC Truck Parts and looked over the various tank and sender listings.

The K5 Blazer lists the same tank, gas or diesel depending on the years.

The sending unit is different however. (Number of lines coming out)

The Burbs show a tank specific to the diesels as do the pickups.

I can't find any definitive answer as to the difference in the tanks.

I can't see why a gas tank would not carry diesel and work just fine ????

OH BTW have a helper get in and press on the brake while you watch under the hood, I am suspicious that your power steering pump belt my be slipping and once this happens the steering will get stiff.

Check it out.

Missy

[DmaxMaverick]

Three things.
1. Does anybody have a rebuild guide for a steering gearbox? Is it hard to do? And where would you get a kit?
2. If i apply my brakes the steering gets real stiff. I already flushed the hydro boost once, should i do more?
3. I got a gas tank of a gas truck and it has three lines out of it. What the third? and is there any way to rig the feed from two tanks to suck evenly to eliminate the need for a selector valve

FYI its a 1987 GMC sierra 1500 6.2L

The steering gear box rebuild would depend on what's wrong. Shaft seals are easily replaced, but internal hard parts not so. I have yet to see a home-job that was less than disastrous. If the steering works fine before you apply the brakes, the gearbox isn't the problem. In all likelihood, it's either a pump delivery issue (low pressure and/or volume) or the HB unit. The usual first sign of HB failure is the loss of reserve braking: idle the engine for a minute with no brake or steering input, turn off the engine, wait 20-30 seconds, apply the brakes in a "normal" manner, count how many times the brake pedal is assisted to about 3/4 pedal travel, if less than 4, it's marginal, if less than 2, it's shot. In either case, a quality reman or new is in order.

The 3rd line on the gasser tank sender depends on the year and/or emission standard. Could be the rail purge on late models (EFI, mostly late port injection) or the evap purge on earlier models.
In any case, there is no functional difference between the models within similar model year series. Just plug/cap the line you don't need. The float will work fine, gas or Diesel. The specific gravity between the fuels is negligible. GM fuel level senders/gages have never been accurate enough for any of this to make any difference you would notice.

There is no practical way to draw fuel simultaneously from 2 tanks on a mobile platform (motor vehicle). The tank levels would have to be "balanced", but that would be a problem anywhere but on level ground while not moving. Drawing fuel from both tanks would also require equal pressure at the outlets, all the time, or one would empty before the other, or one would fill the other, taking fuel away from your supply outlet location. The early solution was the dual tanks with a manual selector valve (switched supply, return, and level sender). The late solution is a dual tank system with the primary tank plumbed like a single tank system, with the secondary tank supplying the primary via a transfer pump (automatically via ECM control according to tank levels), and the fuel level gage indicating an average of the two tanks. Any other solution presents several functional issues, as well as USDOT and local legal, safety, and/or emission concerns.

[engineeradam]

hey guys thanks. im going to just replace the seals on the gearbox then. i thought it was the belt to but its really tight now. i found a selector valve for the gas tank, and im going to try the hydroboost test DMAX described.