1994 International 4700 Conversion Begins

[rossvtaylor]

You gotta love Craigslist! Found the correct tank I was after, now for the fun of figuring out how I want to mount it.

Damn... I love CraigsList and I'm often surprised by what I can find. But... man... you found the perfect tank locally... just what you were looking for, at the right time. That's not a forklift tank, is it? Mind me asking if it was a private party sale and what it came out of?

I did some checking today (and we bought a small grill) and we'll have enough space to put regular vertical 20lb tanks in our exterior kitchen. That simplifies our life... a lot.

 

[scooter421]

It's a "standard" LP BBQ tank designed to sit in the horizontal position. This type can only be used horizontally. It was a private party purchase; so, I saved some money too! He had purchased it for a family member to put in a slide in truck camper but the family member decided they were going to sell the camper. I decided to go this route rather than the forklift tanks due to space limitations. This style is a little easier to come by and a bit cheaper. Now, I just have to get all the hoses and fittings needed, mount it up and I will be all set.

 

[rossvtaylor]

Hey, here's another tank on CL down your way... it's a different format, and 10 gallons (too big to handle easily?), but it looks like a nice design (with a gauge) for $150. That would tuck up nicely...

https://phoenix.craigslist.org/evl/rvd/5671642137.html

Here's a pic of it, so after the ad's gone away others can see what it looks like. If I were space limited, this looks like a neat configuration. The ad says it's a Flame King.

 

[scooter421]

Hi Ross, I did see that unit but I am stuck on having some portability. That one would fit and it's a good price though!

 

[scooter421]

Had a nice time up out of the heat for a couple days, hated to come back to reality! This was the first ride back up the mountain since the tire change. As for ride, we could not be happier and driving through the woods was a smooth ride compared to what was on the truck originally.

However, the extra weight the tires/wheels provide sure made climbing the hills a slow trip to the top! I've got to look into options on changing the gear ratio in the rear differential I suppose. Transmission options are pricey and not "easy" to do. We also have a power steering system that provides the brake pressure as well. I believe many medium duty trucks and diesels come this way. I'm not entirely sure why but my right rear brake gets really hot compared to the other three. I don't know if this is simply the path of least resistance and this one does the most work or what's going on but it gets hot. It seems like if the engine stays up in temp (fan on a lot) eventually the heat transmits to the power steering pump and fluid building pressure and just slightly self applying the brakes. Of course, this just makes the problem worse, the motor and transmission stay up in temp and it's always struggling to cool down. I may have to pull the plug and take it to International for review. We did make it there and back without issue and that's a plus!

 

[scooter421]

As for the brakes, the only things I have not replaced/rebuilt are the lines and master cylinder. I even added a power steering cooler to help keep the fluid temp down.

 

[dwh]

Second that. One of my standard mods back when I was building wheelers was a power steering cooler. It was always the hottest thing under the hood.

Got the idea from a 69 Lincoln I had. It had hydroboost for the brakes, part of the power steering system, and had a factory cooler.

I'm not sure I buy the theory that hot hydraulic fluid is causing a slight application of the brakes. I'd be more inclined to look at adjustment and also for a wear groove on the backing plate preventing the shoe from bring pulled away from the drum by the return spring.

Or a sticking wheel cylinder.

 

[scooter421]

Second that. One of my standard mods back when I was building wheelers was a power steering cooler. It was always the hottest thing under the hood.

Got the idea from a 69 Lincoln I had. It had hydroboost for the brakes, part of the power steering system, and had a factory cooler.

I'm not sure I buy the theory that hot hydraulic fluid is causing a slight application of the brakes. I'd be more inclined to look at adjustment and also for a wear groove on the backing plate preventing the shoe from bring pulled away from the drum by the return spring.

Or a sticking wheel cylinder.

Thanks, DWH

The heat build up seems to be a bit of an issue with this particular braking system and model of truck from what I've read. When I purchased the truck the same caliper had no pad left and was metal on metal. After working on the system multiple times the problem drifted to the other side. I rebuilt everything and I really have not had much trouble until this trip. I wish these calipers had return springs! Other than a lack of pressure they don't really "return" they just..."let go". I am still new to this power steering supplied braking pressure business but I will get it one way or another! It is certainly possible one of the cylinders is hanging up. I may look at this one again in the future but man are they a pain in the neck to get to!

Thanks for the input!

Scooter...

 

[dwh]

Ah. Disk brakes. My comments were assuming drums on the rear.

Yea, calipers don't have return springs. If the caliper has pistons on both sides the caliper might not even be designed to move. In which case it could be a sticky piston.

If the caliper has only one piston, then it's a sliding caliper. Sliding calipers usually slide along a flat machined surface. I always polish the flat surfaces of both the guide rails and the caliper with emory cloth and paint on a decently thick layer of high temp grease so the caliper doesn't stick.

But eventually, those surfaces can wear and the caliper can get cockeyed and stuck no matter what you do. Only fix for that is new caliper mounts and new calipers unless you take them to a shop that can build up the surfaces and then mill them back down to original specs.

If you rebuild the caliper yourself, there is a tool to hone/polish the bore and the piston should be polished with emory cloth. But too much of that and the piston gets sloppy in the bore and is likely to get cockeyed and sticky.

 

[scooter421]

DWH, you're on the money. Rear disk and dual pistons, the caliper is not designed to move and they are certainly not polished by any means. When I pulled them apart they were all in pretty much the same condition. Looked like a pretty sloppy design from the start really, rather rough bores I thought. I cleaned them all up and things have been fine. This seems to happen when I am running the engine and tranny hard and everything is just barely staying cool. My engine seems to be okay around 180-195 plus or minus with the fan keeping it in check. However, in these summer temps the fan is on a lot. The tranny is another story and seems to be running 190+ and creeping over 220 when I am hammering up the mountain in second gear. Nothing is over heating per say but it's struggling to stay cool. When this happens the brakes begin to slightly apply. Not enough to stop me or really even notice but I think this is what keeps the tranny temp elevated.

 

[dwh]

Well, the only other thing is brake fluid. Properly bled the system I assume?

Brake fluid absorbs water from condensation inside the system and that lowers the boiling point of the fluid. So it has to be completely flushed out and replaced every so often.

More than once I've had a "brake job" done at a shop and they didn't bleed the brakes and when I mentioned it they said there's no need to bleed if they didn't open the system and let air in.

Made we want to slap them upside their idiot heads.

You using DOT 3 or DOT 4?

I can maybe see the fluid getting hot and expanding if it has some water in it, but I can't see it being caused by the hydraulic power booster. Maybe a brake line too close to the exhaust or some such thing.


Um...I just remembered an incident from a long time back that probably has nothing to do with anything...

Down in Baja, a guy in our group got a brake line nicked from a rock and lost all his fluid. Pinched off the line so he could keep going, but turned out he didn't have any brake fluid. We all checked our trucks and none of us had any either. D'oh.

Someone says, "I got power steering fluid. Think that will work?" We all look at each other and shrug. "Dunno."

So the guy says screw it and puts the power steering fluid in his brake system.

He could drive for like 20 minutes with the brakes getting tighter and the truck getting slower, then he'd have to park and let it cool off for an hour and then do it again.

 

[scooter421]

Using DOT 3 simply because that's what's called out on the reservoir. I will have to check on the DOT 4, never looked at it. Bled the brakes many times and ran through several gallons over the multiple times working on them. It would not surprise me if someone had put power steering fluid in it in the past. When I picked it up everything was way overfilled and all the fluids were really old. The fluids were a mess to say the least.

What I've read is that the power steering pump can either supply too much flow and the bypass at the booster can't handle the volume of flow through the bypass and slowly applies the brakes. However, I've never come across a pump that pumps "too much" fluid. In my experience a pump only gets worse with age, not better. Then again, I don't know the internals of the power steering pump. Maybe there is some sort of limiting device internally that has worn out...like an orifice or something.

The brakes only seem to begin to drag a little when everything is hot which leads me to believe it's not the pump. The other issue I've read is that the power steering fluid gets hot, expands inside the booster and begins to push on the master cylinder. This seems to be what's happening. Then, as the brake caliper warms up now the brake fluid at the caliper gets hot and pushes a little harder. It could be a bad caliper.
Scooter...

 

[dwh]

Okay, but no matter how hot the power steering fluid gets, it shouldn't be _able_ to push on the master cylinder if your foot is off the brake pedal.

If that actually happens, then it's gotta be something wrong inside the booster, like a leaking piston seal or a weak return spring or something that is allowing fluid to flow to where it shoudnt.

Because normally, with your foot off the pedal, the bypass in/out is the only path available for the fluid to follow (except for a bit bled off into an accumulator).

 

[scooter421]

Absolutely, I replaced the booster and it's been fine until this last trip. Perhaps somehow the Master Cylinder is not allowing fluid to return?

Scooter...

 

[dwh]

Absolutely, I replaced the booster and it's been fine until this last trip. Perhaps somehow the Master Cylinder is not allowing fluid to return?

Scooter...

I think only a clog somewhere would cause that, and with all the bleeding you've done I think that's doubtful.

So back to sticky caliper piston...