HMV #52 motor oil pump

[HMVDevotee]

Hey,guys... any suggestions on the disassembly of the oil pump on the HMV #52 motor? I see that there are three access point to the pump assembly, two on the outside of the casing and one inside. From a previous post (years ago!), a helpful image shows the parts of the pump aligned as assembled (I assume). I was just wondering if there is a proper order for taking this apart and cleaning it and the purpose of the access points.

Thanks, Robert

[HMVDevotee]

So I forged ahead, anyway, and found a back-flow check valve (ball and spring) on the oil feed path from the reservoir, and a similar ball and spring back-flow check valve internal to the sliding cylinder that comprises the actual pump.

Happy to share info with anyone working on a seized oil pump, including a filter I've added to the reservoir to avoid future clogging.

[Inigo]

Some time ago there were posts related to this oil pump recovery, something about a leather or rubber special washer... I believe emgcr was involved in that... Have you done a search on this forum for no. 52 motor or "oil bath motor" as is usually named?

[Orchorsol]

Some time ago there were posts related to this oil pump recovery, something about a leather or rubber special washer... I believe emgcr was involved in that... Have you done a search on this forum for no. 52 motor or "oil bath motor" as is usually named?

That was for a Garrard Super oil bath motor, not HMV, but some features or knowledge may well be similar...

[HMVDevotee]

Inigo (and Andy),

I did find discussions on the HMV Oil Bath motor, but no discussions on the construction of the oil pump. Nonetheless, I discovered that it was a two stage, ball and spring check-valve pump that feeds exclusively from a little hole on the lowest point of the sidewall of the reservoir.

Attached are images of a brass oil filter I have installed in the oil reservoir. It is the same depth as the reservoir and is held in place by the slightest compression from the underside of the reservoir cover and is centered on the cover's "funnel."

With a little luck any hardened grease that becomes particulate matter (that clogged my oil pump in the first place) will be trapped on the inside of the filter ring. The filter may be fine enough to collect the semi-dissolved grease - sludge that settles-out on the bottom of the casing. When I cleaned the interior of the reservoir, I found it filled with a quarter of an inch of petrified grease sludge which had filled the oil pump inlet.

With the motor reassembled with new grease in the spring barrels and new sewing machine grade oil in the reservoir, I figure I will give it a couple of years, or until I observe a color change in the oil, and then will re-open the reservoir to see if the filter had done its job.