1981 straight six manual 4x4 project

Nothing worthwhile is easy.  From what I've heard the hydroboost upgrade is well worth it.  And the wider radiator will be as well.

As for the pulley, belts are quite forgiving.  But, you can put a straightedge on them to see if they line up.

Keep on keeping on.....  

Thanks Gary, I hope it all comes together after I round up all the little odds and ends. I heard about steering twitchiness with some of the GM hydroboost units, but never with the F450 system. I've heard that the pedal feel is more firm, which can be objectionably firm if you don't have the right pedal. But everyone raves about the stopping power. I am eager to test it out for myself. I have also heard really good things about the Saginaw pump, so hopefully that will be worth all the hassle it caused. I found a machine shop in Flagstaff that says they should be able to make the high pressure hose for me 👍

Yesterday I finished the Saginaw pump / Hydroboost conversion and installed the extra cooling radiator. I did run into more uphill nonsense, but progress was made.

For anyone doing a straight Saginaw pump swap, the stock high pressure hose from the van should work. If you are doing Saginaw AND hydroboost you will need a custom hose. I found a shop in Flagstaff that could make me one. Basically they just cut the C2 pump fitting off the end of my hydroboost hose and put a compression fitting on it, and sold me a 3/8" Doorman fuel line repair kit that had the correct end on it. In hind sight I should have had them make me a whole new (much longer) hose, using the hydroboost end in one compression fitting and the Doorman end in the other. The straight six is so long that it puts the steering pump quite forward compared to a V8, so I had to leave a long length of the Doorman fuel line sticking straight back from the pump in order for the hose to reach. It would be better if the hose was longer and the steel line was shorter, but it works. I didn't know I would need that much more length, and a whole new hose would have doubled the price. Here are the parts that I used:







And the brass return line T to join the hydroboost return with the steering box return:



I never did find the correct adapters to use the hydroboost master with the F150 brake lines. I ended up stealing one brake line of my F350 to make it work. They do not use two different fittings like the lighter duty trucks. I will have to get another from the junkyard for my diesel build. The fittings at the proportioning valve are different sizes as well, so switching the whole line is not an option without adapters.



The radiator went in just fine, the upper hose is perfect... I just needed to turn it around! 🙈



While I had the coolant drained, I put in a new 195*F thermostat from Napa (they said theirs are from Stant 🙄)... I might need to get a Motorcraft one? And I replaced the thermostat housing with a newer style one with an extra port for a temperature sensor. I was wanting to keep my stock gauge working while adding a mechanical gauge that I had in my diesel. But... I was foiled again. The probe was hitting the cylinder walls in the water jacket and would not thread in at the rear of the block. It was far too long to fit the port in the thermostat housing as well:



Results for the day: the Saginaw pump works. It is not as quiet as I imagined in my head, but quieter than the C2. It is a used junkyard pump, and I was listening with the hood up and no transmission tunnel cover, so everything was amplified. Steering ease (stationary) seemed good. Hydroboost I can't report since I did not bleed the lines and brakes, and I can't drive the truck yet. I am going to order new calipers, wheel cylinders, brake hoses and pads before I bleed anything. But I did get some pedal and it felt firm as I have heard it would be. So it does at least seem to be working. Wow. That hydroboost reservoir holds a lot of fluid! It's like a milk jug on the firewall!

The truck is still overheating when idling in place. Or seems to be... I only had the stock gauge to go by. It did not completely peg to hot as before, but sat in the little space between normal and H on the gauge. I need to get a real gauge on it before troubleshooting further. The radiator I installed is basically brand new. The shroud is in good shape and has the flexible trim to seal against the core support. The thermostat is new. I do not have a viscous clutch. The fan blades are fixed. I guess the water pump could be bad, but my recollection is that the impeller blades are metal, and when they fail they leak and make noise but still move the coolant. The antifreeze looked clean, I don't have any horrible corrosion problems. I am leaning towards a gauge problem. Any other ideas?

Last thing that I wanted to share is my junkyard find, although I did not install it yet. My front cross member is horribly bent, so I bought a replacement with an upgrade. If I wasn't convinced that I needed this before, Gary convinced me at the GTG that this is a necessity 😎

I noticed my 1981 has an odd rubber cover over the voltage regulator... looks like it might be stock?

Interesting!  Are there any numbers on it?  I’ve never seen one of those that I can remember, but until Matt Vose gave me the one that covers the ignition module I didn’t remember that either. But we sure saw one at the show on that ‘85. Hmmmm...

Wow!  You found a crossmember with a receiver?!?!  That’s cool!  You are really going to enjoy that.

On the overheating, I can’t imagine that actually happening at idle with a new thermostat, newish radiator, good shroud, clean coolant, etc. It has to be the gauge. Can you put the mechanical probe where the stock one is and put the stock one in the thermostat housing?

As for the hydroboost, I’m anxious to see the report on the stopping power. Seems like the firm pedal confirms what you’d read, and you obviously got away from the hiss of the vacuum booster, so you’ve already made gains. Just a bit more work and you’ll have a much-improved braking system. 👍

Man, you are really making progress. 🎉

Thanks Gary, one more good day with it and I should have results on the braking. The mechanical gauge probe won't even work in the block where the stock sender goes. This surprised me, as I've run mechanical temperature gauges in three other straight sixes that I've owned. The probe hits the cylinder wall inside the water jacket. I'm going to have to buy a different aftermarket gauge. Too bad, it's a nice upper shelf VDO with a good sweep. I will see if I can find something with a shorter probe. Might have to be electrical 😐. I'm really itching to try out driving this thing...

More progress, more results, and more challenges...

The exhaust note of my truck resembled flatulance, so I replaced the exhaust donut with a sintered steel one:





I looked at the manual temperature gauge on my 1968 straight six truck and found that it has a brass stepper in between the block and the probe. I went to the junkyard and found one so I could hook up my VDO temperature gauge. I also bought a new temperature sending unit for the factory gauge and put it in the thermostat neck. I know, it needs to be moved to the heater hose side but I wanted to see needle movement when the thermostat opened and compare it to the manual gauge reading in the back of the block. The thermostat opened right about 195*F as advertised. The factory gauge, however, still reads really high while the manual one holds right around 195*F. I tried a different cluster with a different gauge in it and both read high. Both new and old senders read like this so it must be in the truck's wiring or grounds?


Stepper for manual gauge probe


Temporary location for electric sending unit to check thermostat opening...


Cluster #1 temp gauge and mechanical gauge


Cluster #2 temp gauge and mechanical gauge

Anyway, I am satisfied that I no longer have an overheating problem. The factory gauge runs high but it does not peg hot like it did with the old, smaller radiator. The mechanical gauge sits right where it should for the thermostat specification. So far so good.

I did notice that after I got the truck up to temperature, the hydroboost lines and power steering lines were extremely hot... hot enough to give me a slight burn on my forearm (ouch! 😬). So... either I just never realized how hot the power steering pressure lines are or I have a problem. Theory 1 is that my T return line arrangement is not effective. I may have improper flow through the cooling tube. Theory 2 is that I had my foot resting on the brake while I brought the cooling system up to temp. Maybe the hydroboost system didn't like that? But it should be up for constant use in stop and go city traffic? Maybe I should put a finned oil cooler on the hydroboost return line? Theory 3, bad Saginaw pump. I know they "run forever" but it was just a junkyard take off, as is the hydroboost unit itself... any other ideas? I'm going to try again without resting my foot on the brake and see what happens...

Beyond that, I installed new U-joints in both front and back driveshafts and put them back in the truck. I have all new calipers, wheel cylinders, pads and shoes waiting to go in on my next stint.

Wow!  So much work!  And goo work, to boot. 👍

I can’t account for the high stock temp gauge reading, since it does it with two different clusters and two different sending units. But, there’s supposed to be an 8 to 9 ohm resistance wire feeding the system, and without it I suspect everything would read high. You can see the resistance here: http://www.garysgaragemahal.com/fuel-tank-selector--gauges.html. You could check that by pulling the cluster and checking resistance from the power feed to the cluster to the battery’s positive post.

And the way to fix it might be with a real voltage regulator to replace the ICVR. But, if the ICVR or resistor are the problem then all three gauges will be reading high.

Thanks Gary, that at least gives me a place to start. It probably won't take first priority, but I do need to address the gauges... I do get a twitch out of the ammeter which is about all one can really expect, but I am getting zip out of the fuel and oil pressure gauges. I have a matching mechanical VDO oil pressure gauge that will be going in, but again I'd like to have the stock one working. The fuel gauge is a headache that I am not looking forward to. The midship tank was deleted at some point and I have no idea what was done to the tank switch wiring if anything. Best plan right now is to keep 'er full...

Correct, if you have a voltage issue, as the IVR is not doing it's job, you will notice it which all electrical gauges. You could get a voltage reading from the supply line o your gauge to verify.

Pete - The link on the ICVR page to ICVR Thoughts & Observations shows the waveform of the supply voltage to the gauges and senders. I doubt there's a digital voltmeter that will read that, although and old analog would give some reading.

Well guys, I guess I should learn to Google a thing or two before making half baked posts 🙈

Optimal power steering fluid temperatures are considered to be around 180*F, with anything below 250*F being acceptable. Pump damage begins to occur when the fluid temperature rises to around 300*F. So if my steel lines were around 180*F that would explain the ouch on my forearm. I still think I might try to measure the reservoir temp just to be sure, but it does not sound like its abnormal.

http://www.hotrod.com/articles/ccrp-1112-power-steering-coolers/amp/

I am thinking of installing at least a simple inline filter on the return line, and it might not hurt to add a finned cooler from the junkyard but it probably isn't necessary.

Good to know. And I didn’t.

Got the brake job done... all new calipers, wheel cylinders and shoes/pads. Bled out the murky brake fluid and took it for a test drive. This is also the first time I have driven it with the 3.00 axle gears and the close ratio transmission...



First thing I have to say is that the stopping power of hydroboost is RIDICULOUS. There isn't much point in discussing "pedal feel" because you barely have to touch the pedal at all and the truck stops. This thing has the best brakes of any vehicle I have ever owned. The upgrade is totally worth it. Compared to my experience with 80's vacuum brakes it's not just better, it's in a whole different class.

The Saginaw pump is working great also. It is definitely quiter than the C2 pumps I've had. The truck steers great now, and it does not even have shocks or alignment yet. Again, I highly recommend this upgrade.

The close ratio transmission with the 3.00 gears is just about what I expected, but I still need to get used to the spread. I don't think I want to go any bigger with the tire size. 1st is a good start out gear but I don't think I'd want to weaken it at all. I found myself shifting too early, probably  out of habit. I was also driving with no transmission tunnel cover so the engine sounded excessively loud for the rpm. I cannot really comment yet about the top end because I just drove it through the neighborhood and barely got it into 4th gear at all.

I need to do some engine tuning. Deleting the vacuum booster changed the vacuum advance on the carburetor, and it generally didn't run as well after I removed it. I need to check for leaks and reset the timing.

Very impressive progress, Jonathan!

Yes, well done!  So, I should do hydroboost on Dad’s or Big Blue?  I have a  Saginaw for Dad’s, but didn’t use one with two output fittings. Does yours have two fittings?

I would highly recommend hydroboost on either one or both. The Saginaw pump that I found was just a junkyard take-off from an Econoline and has just one return port. I used a brass T to join the two returns. Many have done this and it works fine. Brazing in a second return would be more elegant, or finding a reservoir with a second barb if you can find one. The third option that I like is the filter head solution:



All of the hydroboost parts for the bricknose F-Superduty (F450) are generally available from parts houses or online, except the pedal. That you might have to get fabricated/modified. And if you run hydroboost with a Saginaw pump you are going to need to change the end of the high pressure hose like I did.

Good info. Thanks!  I could add a fitting to the Saginaw for Dad’s truck and re-powder coat it pretty easily. That would be cleaner than a tee as you point out, and that’s one of the goals for that truck.

As for Big Blue, I think I should file that for when I run out of things to do. The list of possible projects seems to grow exponentially.  And, as I’ve told others recently, when I look forward in time I keep seeing a pop up that says “Objects are closer than they appear”.  🙈

Gary Lewis wrote

The list of possible projects seems to grow exponentially.  And, as I’ve told others recently, when I look forward in time I keep seeing a pop up that says “Objects are closer than they appear”.  🙈

That is a very wise plan Gary. As I have said previously I am a bit upset that I let this F150 take up as much time as it has. I never should have bought it and remained focused on the diesel. There are lots of things that I probably *should* be doing "while I'm in there"... but I keep telling myself that I can't get lost in the poppy fields. The potential project embellishments are indeed endless to the detriment of the whole.