L48 split for HST repair

[rbargeron]

Members here may remember this L48 HST story from 2013 . It had developed weak reverse and the repair estimate was north of ten large. The owner decided to sell it as it was, and I adopted it.

With regulator and servo piston adjustments reverse worked again, but wasn't perfect. I've used it that way for quite a while. Its a strong capable tractor. But reverse isn't 100% so it was finally decided to have a look inside.

The ROPS comes off first, then the rear wheels and the main frame. The WSM describes taking off the loader and center console - but they can be left on. The loader posts were unpinned from the main frame and the steering column assembly can lift a few inches for clutch housing access.

The HST has to come apart, so the first separation was behind it. Then the HST was rolled away from the clutch housing.

In the next few days I'll post what was found in the HST and the cure. More old/new pics when swash plate cradle bearings are delivered.

While clutch is accessible, a new disk and release bearing will go in, and new sleeve and seals on the front driveshaft. It hasn't been leaking but you know it will start if new parts aren't installed. Dick B.

 

[Jchonline]

Subscribed, cant wait to hear about it!

 

[dodge man]

I'll keep on eye on this also, curious what you find.

 

[grsthegreat]

Talk about taking on a project. I like doing my own repairs but one of this scale would be way beyond my comfort zone. Interested to see results

 

[rgr33]

Chapter one on this story was great, can’t wait to see how this unfolds.

 

[fried1765]

Members here may remember this L48 HST story from 2013 . It had developed weak reverse and the repair estimate was north of ten large. The owner decided to sell it as it was, and I adopted it.

With regulator and servo piston adjustments reverse worked again, but wasn't perfect. I've used it that way for quite a while. Its a strong capable tractor. But reverse isn't 100% so it was finally decided to have a look inside.

The ROPS comes off first, then the rear wheels and the main frame. The WSM describes taking off the loader and center console - but they can be left on. The loader posts were unpinned from the main frame and the steering column assembly can lift a few inches for clutch housing access.

The HST has to come apart, so the first separation was behind it. Then the HST was rolled away from the clutch housing.

In the next few days I'll post what was found in the HST and the cure. More old/new pics when swash plate cradle bearings are delivered.

While clutch is accessible, a new disk and release bearing will go in, and new sleeve and seals on the front driveshaft. It hasn't been leaking but you know it will start if new parts aren't installed. Dick B.

This story scares me.
I am looking for a low time L48.

 

[Coyote machine]

Members here may remember this L48 HST story from 2013 . It had developed weak reverse and the repair estimate was north of ten large. The owner decided to sell it as it was, and I adopted it.

With regulator and servo piston adjustments reverse worked again, but wasn't perfect. I've used it that way for quite a while. Its a strong capable tractor. But reverse isn't 100% so it was finally decided to have a look inside.

The ROPS comes off first, then the rear wheels and the main frame. The WSM describes taking off the loader and center console - but they can be left on. The loader posts were unpinned from the main frame and the steering column assembly can lift a few inches for clutch housing access.

The HST has to come apart, so the first separation was behind it. Then the HST was rolled away from the clutch housing.

In the next few days I'll post what was found in the HST and the cure. More old/new pics when swash plate cradle bearings are delivered.

While clutch is accessible, a new disk and release bearing will go in, and new sleeve and seals on the front driveshaft. Dick B.

You're right about this: "It hasn't been leaking but you know it will start if new parts aren't installed."
Nothing saved by not doing all of them; BUT if you don't do them, you will pay for sure. Does the input shaft have a pilot bearing? If so, I suggest replacing it too. Good luck! How much time in so far on the teardown?

 

[rbargeron]

...... Does the input shaft have a pilot bearing? If so, I suggest replacing it too. Good luck! How much time in so far on the teardown?

No pilot bearing in this model. And I'm moving at "retired" speed - a few hours at a time. It's actually at the halfway point because its beginning to be reassembled - new clutch and release bearing are installed, front driveshaft parts are next. All parts are ordered, some delivered. New swash plate "bracket with bearings" (EDIT - now expected Wednesday 3/27). Hoping to get it back together enough to run a few days later.

 

[Industrial Toys]

The costs associated with this would be most interesting. Too few people ever mention the most important part.

 

[rbargeron]

The costs associated with this would be most interesting. Too few people ever mention the most important part.

The link in the first line of post #1 above gets into the costs for parts and labor for HST repairs on the L48. Due to this model's large under-frame dealers estimate around 50 hours shop time to replace the HST. The unit itself is currently priced close to $5k. Its component parts are pricey as well. If 3 or 4 major sub-assemblies are what's needed a whole new unit may cost less.

The issue with mine is worn cradle bearings - parts 90. 100 & 110 on attached parts page. Dick B

 

[Tomtint]

I just had to replace a motor in a B7510... Much smaller but similar in scope..I feel your pain.

 

[rbargeron]

I just had to replace a motor in a B7510... Much smaller but similar in scope..I feel your pain.

Now that I've seen inside the HST up close I'm feeling good about its future. The pump and motor show no wear at all. Only the 2 cradle bearings are damaged. One had come loose and was blocking swash plate motion. They are a laminated composite of non-magnetic material (?) Luckily the debris went into the filter without chewing on other parts. The swash plate could use buffing but it has no measurable wear. I'll take pics when the new parts show up.

The clutch housing is back in place (without taking any more apart). The job is just waiting for cradle bearings at this point.

 

[radios1]

The link in the first line of post #1 above gets into the costs for parts and labor for HST repairs on the L48. Due to this model's large under-frame dealers estimate around 50 hours shop time to replace the HST. The unit itself is currently priced close to $5k. Its component parts are pricey as well. If 3 or 4 major sub-assemblies are what's needed a whole new unit may cost less.

The issue with mine is worn cradle bearings - parts 90. 100 & 110 on attached parts page. Dick B

wow, that's a very simple transmission compared to an automobile automatic transmission.. I've repaired many of those..

 

[rbargeron]

wow, that's a very simple transmission compared to an automobile automatic transmission.. I've repaired many of those..

Yes - pretty simple and pretty clever. Variable ratio, reversing and with no slip. Its tight clearances make it expensive to produce - and repair/replace.

 

[rScotty]

Now that I've seen inside the HST up close I'm feeling good about its future. The pump and motor show no wear at all. Only the 2 cradle bearings are damaged. One had come loose and was blocking swash plate motion. They are a laminated composite of non-magnetic material (?) Luckily the debris went into the filter without chewing on other parts. The swash plate could use buffing but it has no measurable wear. I'll take pics when the new parts show up.
The clutch housing is back in place (without taking any more apart). The job is just waiting for cradle bearings at this point.

Did you do some buffing on it? I'm not sure how I would buff that.... Or how to measure the swashplate wear. Maybe just by looking at the fit?
rscotty

 

[radios1]

Now that I've seen inside the HST up close I'm feeling good about its future. The pump and motor show no wear at all. Only the 2 cradle bearings are damaged. One had come loose and was blocking swash plate motion. They are a laminated composite of non-magnetic material (?) Luckily the debris went into the filter without chewing on other parts. The swash plate could use buffing but it has no measurable wear. I'll take pics when the new parts show up.

The clutch housing is back in place (without taking any more apart). The job is just waiting for cradle bearings at this point.

Micarta cradle bearings?. surely, they could have used something much better, but then, it would last too long!.(they like to sell parts)..

 

[rScotty]

Micarta cradle bearings?. surely, they could have used something much better, but then, it would last too long!.(they like to sell parts)..

Micarta?? Well maybe. That surprised me too, although Rick doesn't say if it's a metal or resin composite material. Metal sandwich construction types of bearing material are also non-magnetic and have a long history being used for sliding on curved surfaces - think lower end rod bearings... . So it doesn't have to be a resin type.
For hi-temp, I've seen bearings made of bearing bronze bonded to a backing layer of 316 stainless & I'd have to call that composite construction....it's also non-magnetic.

I wonder why this one came loose? & how to prevent that happening again?
rScotty

 

[rbargeron]

Right about the materials rScotty - definitely not micarta. Maybe stainless with bronze cladding?. Here's a picture of a new bracket with bearings. I've ordered one.

EDIT: Fedex delivered the new bracket today. The brown wear surfaces are bronze. The swash plate fits the cradles perfectly as-is. It has the same surface finish as a new one - not going to remove any material by buffing it. Besides, the satin finish carries the oil film better.

 

[radios1]

Right about the materials rScotty - definitely not micarta. Maybe stainless with bronze cladding?. Here's a picture of a new bracket with bearings. I've ordered a new assembly like this.

it looks like brown paper over the bearings to protect them during shipping, that is supposed to be removed before assembly. under that, it looks like silver over bronze, which is the better method of making friction bearings, they last much longer than bearing bronze bearings..

 

[rbargeron]

Here's a WSM page showing where the cradle bracket goes in the unit. After bolting it in I solvent cleaned the surfaces and put the port block back on with Permatex Ultra Grey (no gasket). HST is ready to reinstall.