B7200 HST, 1640 Loader Lift and Bucket Cylinder PN

[CJN8]

I am in the middle of re-sealing my lift and bucket cylinders on my B7200. I downloaded the manual for the 1640 loader and my unit falls in the SN number range =>24005473.

From the manual
lift cylinder PN 70050-93634
bucket cylinder PN 70050-93635

PN stamped onto the cylinders
lift cylinder PN 1334036 A08M
bucket cylinder 1334045 A08M

Has anyone seen this? When i look up the PNs from the manual the pictures from the internet do not look like my actual parts. I want to order the seal kit but do not want to order the incorrect PNs.

 

[CJN8]

I am about half way through the rebuild of my hydraulic cylinders. i have two of them apart and I am waiting for the seal kits to come from coleman. After taking apart the cylinders I see a difference in that the lift cylinders have thicker shaft diameters. That explains the difference between the PNs.

While waiting for my parts to come in I have decided to get a cylinder hone and run it through the body of the hydraulic rams so everything seals nicely. I have run into an issue though. One of the lift shafts is gouged. Not sure how it happened. What do you think? How should i go about fixing this? Should I just make sure it is smooth and put it back together? Should I take it to a shop?

 

[North Idaho Wolfman]

IMHO that cylinder rod is toast, there is not much hope of fixing it via normal methods.
I would just cut your losses and get a new cylinder.

 

[D2Cat]

What to do depends on the location of the gouge and how deep it is. The picture makes it look like it was hit with an angle grinder. If you could buff it out where there are no sharp edges it might work fine. Is the gouge located where it passes through the seals? If not, it doesn't matter.

I had a cyl. on my trencher that had a scrape going down the tube several inches. The hyd. shop said it was no good and not use it. I took a piece of 3/8" all thread and attached one of those sanding disc that are about an inch wide and several layers of emery paper connected at the center. I used my variable speed drill to go up and down the tubing for several minutes. Polished pretty nice. That was 12-15 years ago. Still using it to this day.

I also had a slightly bent rod on a cyl., same machine, digging boom. I just reversed the entire cylinder. Then the curved portion was only passing seals when digging at full depth. Which wasn't as often and the other direction. Worked fine.

 

[CJN8]

So I read a few articles that say you can braze the gouge and smooth out the repair and still have the shaft be serviceable. Interesting.

http://weldingweb.com/showthread.php?172251-Brazing-rod-hydraulic-cylinder-s-rod-that-is

 

[cb750k8]

There are two gentlemen on the internet Keith Fenner (Cape Cod) and Abom79 (somewhere down south in the US)who are well equipped and who do cylinder repairs and lots of other repairs on all sorts of machinery. I have watched their videos and have not seen them do that type of repair but have seen Abom79 do what he calls metalising,

Before deciding to scrap your cylinder I would:

1 Talk to your local shop and hear what they have to say.
2 Send emails with your photo to above gentlemen and they may have suggestions.
3 Shafts come in standard diameters and if you could source a shaft (from a scrapped longer cylinder) your local shop may well be able to remove the ends from your shaft and weld/machine them on to the replacement shaft and put you back in business at cost less than that of a Kubota new cylinder.
Good luck

 

[CJN8]

Well if my repair efforts fail, Coleman has the rods on their website for $131 a piece. Not terrible.

 

[Lil Foot]

When I rebuilt my backhoe, one of the stabilizer rams looked pretty similar. I took it to one of the shops here in phoenix area that specializes in this exact type of repair- they turn it down, re-plate it with chrome, (.030 thick instead of the usual .003-.005 thick) then grind it back to original size. They repair all the heavy equipment cylinders in the state. The repair was perfect, but expensive.
($270) Last year, my buddy & I took a much smaller shaft from his Yanmar steering knuckle in for the same repair, & it was $495!!! The shop explained that the obama administration had made it almost impossible to perform chrome plating anymore- raising taxes, licensing fees, hazmat permits & disposal costs in an effort to kill the industry, as they had with lead refining & the ongoing attempt to kill coal in this country. They weren't sure how much longer they would be in business, and that most other platers were already in the area were already gone.
So I guess I'm agreeing with NIW- might be cheapest & easiest to just replace the cylinder, but I'd be interested to see one of the repairs mentioned if you go that route.

 

[Orangefox40]

Just a note about the gouge in your cylinder. This may have been caused by the bucket stop (small steel block) that is attached to the loader forearm. I had a similar situation but caught if before the damage was done. If the drift pins that hold the bucket to the loader arms are worn they will cause the cylinder to hit this stop instead of the stop plate mount on the bottom of the bucket, and cause a gouge in the cylinder similar to yours. They don't have to be worn very much. Finding new drift pins is a bit tricky cause Kubota want your left arm for one pin.
Ron