Jump to content

1486 pto needs engine reved up to engage, diagnosis


acem
 Share

Recommended Posts

My 1486 pto (twin shaft, old style) will not engage unless I rev the engine way up. Then it kicks in hard when it starts. After the pto has operated I can sometimes start it back at idle but sometimes must rev the engine.

It does not slip when engaged at any rpm once it's engaged. The pressures check out ok which engaged.

By searching the forum apparently it could be the the suction seal or seals inside the clutch pack.

I currently have the hydraulic fluid drained. 

How can I check the pump suction seal? 

It would be easy to change now.

Any other suggestions.

Thx-Ace 

Link to comment
Share on other sites

Suction seal is on the pick-up tube.  Unbolt the tube from the pump body and pull it out.  It's really just a visual inspection for damage...maybe a little "feel", too - so it's 'snug'.  Other than that, it's pretty much about getting in a nice "intermediate" position on the tube/in the bore.  Been a while, but I think it's a lip seal - if so, lips face away from PTO.  Also - look for any cracks around the mount tang that could suck air, and be sure the suction strainer screen up inside the pickup tube is clean.

Piston seals are about the last thing to come out.  If you hold pressure once you get it, I'd guess it's not them?

Link to comment
Share on other sites

My thought on that pickup seal. On the level it is below oil level. My problem with them leaking was pto would stop going down hill. With the oil out. Reach in through third link cover. If tube is tight. It's probably fine. If it's loose it needs fixed even if it's not giving problems

Link to comment
Share on other sites

Never seen a suction tube seal fail its usually always an internal problem time to do a pressure check which means putting the hydraulic oil back in (bummer) unless you want to pull it now and have it serviced while the oil is gone

Link to comment
Share on other sites

1 hour ago, snoshoe said:

My thought on that pickup seal. On the level it is below oil level. My problem with them leaking was pto would stop going down hill. With the oil out. Reach in through third link cover. If tube is tight. It's probably fine. If it's loose it needs fixed even if it's not giving problems

Good luck reaching the tube thru the third link cover  I never could 

Link to comment
Share on other sites

Slow or delayed startup is often caused by worn discs requiring a lot of fill oil to move the piston out.
Worn clutch drum teflon seals or wear in the bore. 

Regarding the suction tube seal, I center it up, braze the tube to the clamp and shim between the clamp and bracket to square the tube seal to the bore. 
Photos added along with some helpers I had on a service call to repair this 806 PTO.

 

DSCN3723-002.thumb.JPG.54a94fb4da9a9d73b3d01b70e8c81978.JPGDSCN3722-002.thumb.JPG.868d487efc033f39ecaa7c2c18927949.JPGDSCN3725-002.thumb.JPG.c350a4e822b2445eeceebcdfc96f7d60.JPG

  • Like 2
Link to comment
Share on other sites

 

36 minutes ago, Maynard said:

Slow or delayed startup is often caused by worn discs requiring a lot of fill oil to move the piston out.
Worn clutch drum teflon seals or wear in the bore. 

Regarding the suction tube seal, I center it up, braze the tube to the clamp and shim between the clamp and bracket to square the tube seal to the bore. 
Photos added along with some helpers I had on a service call to repair this 806 PTO.

DSCN3723-002.thumb.JPG.54a94fb4da9a9d73b3d01b70e8c81978.JPGDSCN3722-002.thumb.JPG.868d487efc033f39ecaa7c2c18927949.JPGDSCN3725-002.thumb.JPG.c350a4e822b2445eeceebcdfc96f7d60.JPG

 

This is what I found at removal...

DSCN3694-001.thumb.JPG.5cd2745f54fb277af67f3eb46a82736d.JPGDSCN3702-003.thumb.JPG.24bd602eb39a9829f74fa66a696ec574.JPGDSCN3703-001.thumb.JPG.ac066dbef1848d51bce71f3e6179fa09.JPGDSCN3704-001.thumb.JPG.7d60b1762329d65208dce5a1760bb641.JPG

Link to comment
Share on other sites

Sounds like Maynard has a good handle on it. and many others are on the track as well. Most (I'm aware of ) suction pumps are gear and gears do wear over time even when immersed in oil, but it would take many multiple thousands of hrs of wear. Could possibly be the seal between the gears and housing or a crack in the pickup tube. leak where the pickup tube is pressed into the housing. If you already got the oil drained, the messy part is already done eh! Next comes the fun part requiring 17 fingers and 3 hands all attached to limbs that bend in 7 directions, 5 floor jacks, 4 chain hoists, and 2 com-alongs. Plus a truckload of cribbage, (wood not the game) and support timbers & stands. Just scatter the parts about the floor, the janitor'll sweep it all up when you finally give up and give it away for scrap.

PS: You could always just trade it in on one of the fancy new ones that you can't fix anyway, and when anything goes wrong just trade it on for another new one. Hey, it's the American way, the way modern merka does it. 

Link to comment
Share on other sites

Service manual gives a pressure drop spec from rated speed to idle. Pressure shouldn't drop more than 40 lbs. If so I would strongly suggest wore seal rings and or lining wore on plates

  • Like 1
Link to comment
Share on other sites

3 hours ago, ksfarmdude said:

Good luck reaching the tube thru the third link cover  I never could 

Never had a problem reaching them there. Right under shaft. Can tell if they're loose or not. Doesn't matter who's right on this one. It's not going to work right until pulled and rebuilt.

  • Like 1
Link to comment
Share on other sites

'bout $60 for just seals and gaskets (not from CIH, tho, I suppose); $60 more gets you steels and frictions, and $60 after that gets you brakes.  Add another hundred and you can get a really nice version of the the return spring compression tool....but a couple bolts and nuts, some all thread, and a chunk of steel bar and you can make one.  I'm sure you could do it in an "H" press, too - you really can't do it by hand.

  • Sad 1
Link to comment
Share on other sites

I've got a hydraulic capacity kit from a project that never got done. I've rebuilt a few but it's been a long time.

I just hate pulling them in and out.

Thx-Ace 

  • Like 1
Link to comment
Share on other sites

4 minutes ago, acem said:

I've got a hydraulic capacity kit from a project that never got done. I've rebuilt a few but it's been a long time.

I just hate pulling them in and out.

Thx-Ace 

I use my cherry picker and a long pipe on the shaft really works well

Link to comment
Share on other sites

39 minutes ago, ksfarmdude said:

I use my cherry picker and a long pipe on the shaft really works well

You know. I've threatened to weld a 540 quick release yoke to a pipe just for this job. Would sure help because you could push or pull. 

  • Like 1
Link to comment
Share on other sites

4 hours ago, Missouri Mule said:

What in the world is all that? Looks like hair. I see the cut o ring too. 

It was grass that had wrapped around the PTO shaft and forced it's way through the seal that did not have the brass shield washer installed during the last rebuild.

The fodder was packed in there tight enough that it did not leak too much. 

First time I had ever seen that happen to that extent.  That was from June of 2017.

 

  • Like 1
Link to comment
Share on other sites

11 hours ago, Missouri Mule said:

You know. I've threatened to weld a 540 quick release yoke to a pipe just for this job. Would sure help because you could push or pull. 

Have one, I made, works great. Bout  3 foot long and a T handle on the end to turn the shaft when installing so someone doesn't have to bump the starter

  • Like 1
Link to comment
Share on other sites

On 8/15/2021 at 3:51 PM, Missouri Mule said:

What in the world is all that? Looks like hair. I see the cut o ring too. 

Is that goat hair in the Hy-Tran?

Drain the entire rear end, new filter, overhaul the PTO, clean the suction screen and after 5 hours, do another filter. 

You have a mess in there!

  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...