Thanks again MEngr & Swoop,
You guys are a good help! In reading your last postings a thought came to me about our F03 tilt issues. I had forgotten since we use it so rarely that before the forward tilt quit working we had to really rev up the engine to get it to tilt forward. So this must have been a progressive rather than single event failure in case that would prompt any thought on your parts. MEngr, you mention similarities in the '87 to '93 parts. Do you have a resource that would be helpful for when we get around to working on our F03? We are presently under a time deadline to finish building our wildland firefighting water tender which has turned into a huge project in cutting in half a '95 IH 4900 and '79 GMC 7000 to mate the GM rear frame to the IH power end. We do want to try to get the F03 worked in as we go, so your input is much appreciated...Jim

given the span between '87 and '93 thats a pretty wide span of time.
I'd be willing to bet that even though they look similar there have been changes made even, slight ones that may make all the difference in the world when it comes to identifying the parts and getting the numbers for them.

I would make sure i had the right manual according to the serial number of the truck before trying to determine the breakdown of the valve if it were me. And if this is a japan built truck it could be one of those gray market trucks which can be aggravating to get parts for because of that ;o)

valve assemblies have different part numbers, however they look to have the same makeup.

Howdy MEngr,
Thanks a bunch for your helpful info postings. That could be a big help in knowing the year model as the factory service model we bought for a '93 model off ebay may be different from what was on on the 1987-8 model. Would you happen to know if the '87-'93 models would have the same hydraulics on the tilt?
Thanks again, Jim

Just to add a foot note:
Truck was produced in Murayama, Japan in July 87.

Inf1030
The F03 was equipped with a tilt lock that was inside the tilt spool and it also had it's own relief valve. In the hydraulic also was a flow check ball. This is were I would go to the load check poppet and spring that are sandwiched between the valve sections.

Not familiar with that particular model but some older lifts also had a separate tilt lock valve which is plumbed between the control valve and the tilt cylinders. If not then it is integral in the tilt spool as swoop mentioned.

That bleed off over time is normal. All cylinders will drift a certain amount anyway. As for which way it is or isn't working has to with the control valve in most cases, usually a check valve. In some cases I've seen a hose collapse inside and block the flow too. Since both sides are tied together all it takes is one to get blocked.

Howdy bbforks and swoop223,
Thank you both for your neighborly replies. I should clarify the tilt cylinders do move in one direction (up). They will not tilt down. We can leave it sitting with the tilt up for a few weeks and it will very slowly bleed off to the forks lowering back close to horizontal to the ground. Both your suggestions are much appreciated...Jim

alot of the older tilt spools had internal check valves built into them.
You can remove the top of the spool and there are small poppets and springs in there. One of them might be stuck. If it does not have this then the check valves are on the control valve in the tilt spool section.

just a thought that came to mind while reading this thread
:o)

I'm almost positive that your lift is 100% Nissan. If the lever which works the tilt does indeed move the spool in the hyd control valve & the tilt cyl's don't move I would highly suspect the control valve as being internally faulty. Lifts as old as yours don't usually have any electric control spools on the control valve- you should check to confirm this.

If there's no electric spools & the tilt spool is free & sliding in it's bore than a rebuilt control valve would be my choice. I wouldn't disassemble the control valve & try to repair- there are no parts available & the liability would be over the top

Howdy RCAVSTOR,
Thanks for your reply. Our forklift has the Nissan name on it and I've not seen any Mitsu badging, but of course, that does not mean it is somewhere on it. I contacted Nissan support. They nicely gave some info, but said their computer records do not go back to the late 80's-early 90's which this vintage of the Model F03 is. I located a factory service manual, era '93 on ebay, so hopefully that info will be sufficiently similar to give us some guidance on repairing the tilt hydraulic valve. Since we don't need it and are **** about anything we are selling being in as near perfect condition as we can make it. That is the only thing less than perfect operating condition. It is such a good machine, I hate to let it just sit and be used only 3 or 4 hours per year. Once ready to go, I guess we will put it on ebay. I sure appreciate your taking time to reply and will certainly keep your advice in mind as we blindly tear into this. Thanks a bunch.
Jim

Probably a Mitsu badged as Nissan. If so, these had lift interlock. A quick look @ control valve will confirm this if it has coils on it

Howdy bbforks,
Thanks for your reply. The numbers on the ID tag are UGF0340Y and UGF03-000594. It is hydraulically operated and we figured the valve may be stuck as the forklift has been sitting unused for a good while. We were hoping there may be a trick to freeing it up. We tried putting down pressure on the forks with a backhoe bucket while holding the lever in the down tilt position, but it did not budge. We can see/hear that the pressure is being applied on the tilt up side, but does not seem to be going to the tilt down side. We've been checking the internet to try to find a shop service manual for this model. Thanks a bunch for your input...Jim

A full model & serial # would be a great help for diagnosing but a guess is a faulty hyd control valve unless yours is electrically operated then it could be either a switch or wiring