BOBCAT Bucket Positioning Valve

[DVHammer]

New to your site and hoping someone can help.

I have a 1994 Bobcat 7753 with a bad cab design that traps moisture between the sound deadening foam and the bucket positioning valve and causes extensive rusting of all metal parts that are in contact with it. Including the 'plug' which rusted through and is now spraying hydraulic fluid.

I am looking for Bobcat part number: 6647779 (plug)
This is the OLD part number (described as "WAS" in the diagrams) and is now listed as part number: 6667176 which I have and does NOT fit.
Link to bobcats diagram and is 'ref 9' on this diagram: https://www.bobcatpartsonline.com/#...ydraulic System/0013-Bucket Positioning Valve

Somewhere along the line Bobcat changed the valve body now and want almost $800 for the entire valve body because they no longer have part number 6647779

Have to think there is at least one of these parts on a shelf somewhere. Hopefully someone here might have a lead as to where to find it.....

 

[crewchief888]

did you get the new plug from a local dealer?
if so return it to them and show them the old plug...

it's possible there was a mix-up either at the warehouse, or in OPC.

either way the parts dept can sort it out.

 

[DVHammer]

Yup came straight from the Bobcat dealer here in town where we bought it new back in 1994 so they had all the correct info. Once I realized it was the wrong one I brought the new and old parts back to show them that they were nothing close to the same, they did take it back no questions asked.

They did look into and were able to find out that Bobcat did change valve bodies somewhere along the way and 'told me' that they did some looking with no luck. I have started to look myself and am coming up with the same results as them both with the part numbers and that there is nothing readily available.

They provided me with another possible replacement: Eaton 16224-053 that I am also coming up blank with.

 

[crewchief888]

there were a couple different valves back then...
i wonder if a trip to a hyd supply place might find you a plug that fits..

i'm assuming this is the allen head plug in to top of the valve facing up ?
i havent tried it, but i wonder if a regular hex head plug will fit in the recess the plug is in... maybe grind off the corners of the hex?
for a L O N G time bobcat didnt even list a PN for the oring for that plug.

 

[DVHammer]

Bobcat tried our local hydraulic shop and they were the ones that supplied the Eaton part number.

It is not the one that faces up. It is next to the throttle under your right thigh as your sitting in the seat with the cab down.

going to try and upload a pic of the valve. It is on the far right side facing the back, you can see the throttle at the top of the picture and the black to white line on top of the valve body. It looks like a white stripe where the rusted metal was blown away by the pressure washer. It's the plug right where the white is.

 

[DVHammer]

Here is the part out and bead blasted. You can see the tiny pinhole that rusted through at the top of the pic, when running it looks like a pressure washer spraying hydraulic fluid.

 

[Theweldor]

If you absolutely can't find one I would think if you know a good machinist he could make one very easily.

 

[DVHammer]

Yup, I agree.
Already thinking it through and working on a plan 'B' because I am not very hopeful. But need to exhaust all avenues before jumping in.

Hoping someone will save the day before I get to that point.

 

[Theweldor]

Unless that is some off the wall thread a standard o-ring seal plug should work. It just won't have that long of a head on it. Most of the o-ring seal fittings are a fine bolt thread of some size. Might give you a place to start.

 

[DVHammer]

Good thought on a different piece made to fit. Definitely worth pursuing while still looking for the original replacement.

Long head is there to hold a spring that fits about 1/3 inside but still sticks the other 2/3 onto which spool fits. I will take a pic to better explain when I get to the shop today.

 

[crewchief888]

i see... thats the real early design valve..
it's not just a plug it's the spring retainer...

only ones i see that are rusted that bad are machines that have been around a LOT of salt or chemicals... and never cleaned afterwards...

 

[DVHammer]

Yes it IS the spring retainer so the extension needs to be there.

Not the case here. We bought if new in '94 and has always been kept in a heated shop. No salt or neglect, in fact it was probably over washed. Whenever it was slightly dirty it was hit with the power washer. It's 24 years with only 1600 hours on it.

I believe the problem was the cab has foam under the seat and surrounding areas either for sound or heat and once wet has no way of drying. The foam was squished tight to the valve so it has probably been wet for the last 24 years.

 

[DVHammer]

OOPS!
Thought I would throw a patch on the pinhole and see how long it would hold until I find the replacement.

Weld it? Braze it?
Welder was hooked up for a quick spot so opted for that.

DAMN!, as I pulled the trigger it dawned on me "It's RUSTED!" Not sure what the hell I was thinking, it's rusted so thin there is a hole in it.
So much for Plan 'B' and fixing it.....

 

[05sprcrw]

Could you cut that bit off, and make an extension out of steel bar stock that you could weld to the hex or a new fitting and drill down through it with an end mill to get back to the depth that is on that one? I think a guy could fab that fairly easily if you have access to a mill or a rigid drill press to get the hole down the center to the depth required.

 

[crewchief888]

if i get back to our shop tomorrow and have a chance, i'll do some checking on that PN for ya...

 

[DVHammer]

if i get back to our shop tomorrow and have a chance, i'll do some checking on that PN for ya...

That would be AWESOME!!

05sprcrw:
We are on the same page. I picked up an all thread connector that has a hex on the outside that should pretty closely match the old one and enable me to put a wrench on it for tightening. I plan on drilliing out the threads, press fitting a bar stock to the correct depth to match the old one, and then simply weld it in place to seal it.

 

[05sprcrw]

Sounds like you got a plan if they can't find the part for you at least.

 

[crewchief888]

the old part number definitely crosses to the new number.

i mentioned previously there may be a mix up in numbers on the OPC, (bobcat secure site references the same number) or there may be a mixup at the warehouse....

both have happened before..
i'd be bugging the dealer's parts dept to find a solution.
that is their job

 

[DVHammer]

Wish they thought about it the way you do, I would be back up and running by now.

Spent an hour on it last night.
-Threaded the old piece into a spare fitting to save the threads and enable me to chuck it up in the lathe
-Turned it down to some solid steel
-Bored my hex adapter down to .486 which left slight threads
-Welded it together with a .484 rod inserted to keep it aligned for welding
-Cut off a bolt and ground a slot for adjusting the spring depth to match the old piece at 1.1289
-Once there welded the plug in place to hold it and seal the end.

Had no fluid so could not test it but now questioning the fluid:
Do I need to run "BOBCAT" oil at $60/2.5 Gallons or can I use something from NAPA or Fleet Farm that would be more like $35/5 Gallons.

If so what weight am I looking for??

 

[05sprcrw]

Looks like that should fix your leak. I believe the bobcat oil is a synthetic AW 46 weight hydraluic if I remember right. Around here it was going to be within $10 of what the dealer wanted and no one stocked it, so I was going to have to wait. I just ended up picking up the bobcat oil so I was back up and going and didn't have to worry about not having the right stuff.