L48 split for HST repair

[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.