Volvo D4 raw water impeller change

[pleeson]

Hope everyone is finding ways to enjoy boating in the pandemic era. I'm part way thru an impeller change on my C28 and pondering how to get the new o ring into place and for it to stay there long enough to bolt the two parts of the housing back together? Of course you get around the o ring pressing into place with every finger of two hands and there is about a 1/4" leftover, and/or it pops out elsewhere. Is Vaseline really the best way to "glue" the o ring in place long enough to reassemble? Onto successful discoveries... Getting the old impeller out ain't exactly fun in the confined quarters we are talking about but liberal use of WD 40 around the vanes and into the shaft opening, waiting a few hours, and then just bumping the starter meant that it slid easily off the shaft! Hallelujah! Cleaned up the WD 40 and coated the inside of the housing with liquid dish soap, the splines with grease, and compressed the vanes in the direction of rotation with a cable tie until the impeller was well started, and Bob's your Uncle! Now for the damned O Ring puzzle? Any suggestions?

 

[trailertrawlerkismet]

My go to for the O ring has always been Vaseline. Having changed the impeller on our D4 last fall I can attest to the difficulty getting it out for the first time. Thanks for the tip regarding the ignition to help the situation.

Jim F

 

[S@LTD]

If you have any pool and spa lube that works too as it is designed for rubber O rings on filters etc to help seal and is tacky enough to stay in place. Glad the impeller removal tip worked for you too. Also, there really is no need to wipe out the WD 40 and grease the new impeller. The residual WD 40 will not hurt the new impeller and should give enough lubricant to slide in the new one. I too used a zip tie until it was slid in far enough. I only wish I would have learned of this trick before buying vise scrips, a removal tool that didn’t work and a whole lot of grunting!

 

[baz]

I've changed raw water impeller on my R25 Classic, R-21EC and each time I did not bother to align the impeller vanes for the impeller's intended rotation. Once the impeller starts to turn after the pump has been bolted up, and pulley belt reset, the vanes will bend naturally to the way they need to be. The vanes rotate in an elliptical housing and there's one spot where the vanes are almost straight and as they rotate past this point they will be naturally bent correctly.

Vaseline is used by many here, but the instructions say to use glycerine that typically comes with the impeller replacement kit. My understanding is that Vaseline is not friendly with the impeller's material. It's a shame a gasket isn't used in lieu of the O-ring IMO.

I wish there was a 'sure way' when to know when the impeller needs replacing, other than a failure with engine heat alarm sounding. Each time I've replaced the impeller, the old impeller has always been in good condition; no cracks and no missing vanes.

One tip I recommend when changing the impeller is to ensure any residual salt water that may have drip out of the pump housing and onto engine parts, be wiped up to avoid the rusting issue. Also have a towel under the pump housing to catch things like bolts that could easily slip and fall.