Attempted Shaft Sleeve Remedy For Leaking Jabsco 2760-003 Seawater Pump

[rardiH36]

In a recent thread, Kloudie1 shared that SKF makes a product called Speedi-Sleeve. It is a very thin walled sleeve that fits tightly over a scored shaft so that a new seal has a smooth surface rotating through it.

When inspecting again the shaft after a recent not quite successful new seal attempt to stop my Jabsco 2760-003 seawater pump from leaking, I noticed it (the shaft) was in fact scored.

The 2760 pump has a 3/8” diameter shaft = 9.525mm. SKF's smallest speedi-sleeve is 11.99 mm. I could not locate another manufacturer offering a 3/8” sleeve.

But I did come across on ebay a 10mm O.D. stainless steel tube with a very thin 0.3mm wall – which yielded an I.D. only 4/1000” smaller than 3/8”. Maybe worth a DIY sleeve attempt? I ordered.

A 3/8” drill bit easily reamed out the 4/1000” ID undersize. The reamed out length slid snugly over the shaft. The tube is the welded type, so it had a very slight ridge along the weld line. Scraping with a sharp box knife took this down. Then I smoothed with 1500 grit wet/dry sandpaper. With a Dremmel cut-off wheel, I cut a length slightly longer than the 7mm thickness of the oil seal body. Smoothed out the burrs so the seal wouldn't be damaged during installation. Put a very thin layer of epoxy to the inside of the sleeve. Then with light taps on the sleeve lip using the blade edge of a slot head screw driver, slowly drove the sleeve along the shaft to the spot where the seal resides. Wiped off the epoxy that had transferred to the shaft. After the epoxy cured, I reassembled as normal the seal, o-ring, cam, impeller, gasket and cover.

Mounted on the engine today. No drips after 10 minutes running. Will report back again after an outing or two.

While at it, I did the same to my older previous pump as well.

 

[kloudie1]

Nice ! I noted that the smallest SKF size is a half inch. I know that the pump on my Yanmar is a half inch; I didn't think there were 3/8 shafts out there.

 

[rardiH36]

Nice ! I noted that the smallest SKF size is a half inch. I know that the pump on my Yanmar is a half inch; I didn't think there were 3/8 shafts out there.

Hi Kloudie:

Actually the seawater pump that Hunter installed on our QM20 series engines was not from Yanmar.

As I have posted on the Cherubuni forum a few times as explanation to new purchasers of Cherubini Hunters:

Our engine coolant setup is a bit odd. My "theory" is that around the mid/end of the 1970's, when Yanmar was phasing out the QM's for the next generation GM's, they realized they were overstocked with the fresh/seawater cooled versions of the QM's. So they might have offered them to Hunter at a big discount compared to the new antifreeze cooled GM models. Also around that time, new owners were wanting engines with anti-freeze circulation through the block. So Hunter/Yanmar did an aftermarket workaround to utilize the remaining seawater cooled QM's. They re-routed the hoses so the original engine integral fresh/seawater pump, instead of pumping seawater through the engine block, would do the antifreeze circuit. Then they added an external belt/pully driven Jabsco 2760 (which has the 3/8" shaft) to pump seawater through an externally mounted Sen-Dure heat ex-changer and out through the exhaust elbow.

Yeah, it is confusing!

On my QM engine, because the engine integral pump was originally set up for seawater duty, it has a flexible rubber type impeller -- not the centrifugal type -- even though it now circulating anti-freeze through block. I have replaced this impeller 3 times over the 10 years I have owned my boat. Each time the used impeller still looks great. Little wear. No cracks/tears. I am thinking that the green anti-freeze I use provides lubrication compared to seawater.

Reverting back to the DIY sleeve repair topic. What I don't know is the grade of SS steel the eBay tube I bought. I suspect 304. Not 316. Time will tell if its an issue that will lead to quick failure of the mod.

 

[Jim Legere]

That is a commendable repair job, rardi! It will be interesting to see how it holds up. I suspect the 304 versus 316 stainless alloy will not be an issue. My understanding is that stainless steel is most vulnerable to stagnant salt water, so maybe not a problem in this application. I have had OK results using epoxies like JB Weld on different kinds of worn shafts; it would be interesting to compare the longevity of epoxy to sleeving. (I suspect the sleeve might win).

 

[Dennis Kitchen]

Nice save!

 

[rardiH36]

Two outings now since putting the sleeve over the shaft in the attempt stop the seawater leaking through the newly replaced seal.

Totally dry! So looks like the mod will hold until/unless the sleeve prematurely becomes corroded and/or scored. But considering that the shaft itself did the same after only 2.5 years and 150 hours ... shouldn't be much worse? The main risk to failure would be that the epoxy "weld" of the sleeve to the shaft doesn't hold.

In case anyone is thinking to try the same, I subsequently encountered a possibly better suited SS tube for the sleeve. Per the URL at the end of this post. According to the site, the material is mirror polished Marine Grade 316 SS. 10mm outside diameter with an option of 2mm thick wall. This yields an inner diameter of only 3/1000 inch larger than the 3/8" shaft. So with the inside of the sleeve wetted with epoxy, should be a good fit. Price is right! Because of good prices for multiple items (like a 10 pack of JST power connectors for model airplanes) and sometimes not even available on-line from US sources, I have ordered items over the years with the e-packet shipping from China/Hong Kong. They always gets here.

In the case of 10mm OD, .2mm wall thickness tube, I couldn't find anything similar on the internet with U.S. sourcing.

The seal that I used is sized 10 x 19 x 7. (10mm id x 19mm od x 7mm thick.)

http://www.ebay.com/itm/Stainless-S...hash=item4b10c46508:m:mZjlNlz0iRAEELYsYicPQZQ