70's vintage 2 stage has a bad hi-side valve

by Mathew Banack
(Round Hill, Alberta, Canada)

70's vintage 2 stage air compressor

70's vintage 2 stage air compressor

70's vintage 2 stage air compressor
70's vintage 2 stage air compressor
70's vintage 2 stage air compressor
70's vintage 2 stage air compressor

pulley diameter about 16" 2 groove vee belt.

came to me on a metal skid with a 3phase motor I'm replacing with 5 hp 220v single phase. No tank or any id anywhere.

9 head bolts, aluminum head. 12 bolts holding cyl base to crankcase.

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Nov 06, 2016
Information to share on Brunner compressors...
by: Mike Stubblefield

Looks like it's been a couple of years since the last comment, but for anyone who might be looking, I've been in contact with the folks at Atmosphair in Canada, regarding a Brunner compressor I got for free on Craigslist.

The gentleman that I've been speaking to purchased all of the remaining Brunner parts when the company finally folded (1985 in US, 1994 in Canada). He has also sent me PDF copies of many original Brunner documents, including specs for the various pumps, tanks, and motors. One of the documents has bore/stroke numbers, which could be very helpful in identifying the model # if the original sheet metal tag is gone.

I'd be glad to share them with anyone who may be trying to get information on their Brunner. (Mike has been asked to send them to me so I can upload them for all to download whenever they wish - Bill)

I'd love to talk to more folks about the compressor I'm working on, and hearing about their's.


May 20, 2015
Parts available in ontario
by: Anonymous

Atmosphair - search on the web has parts. Complete valve kit is about 70$. They have gasket set and rings too.

Sep 10, 2014
Brunner Parts
by: Anonymous

Looks like there might be some light at the end of the tunnel for Brunner parts:


Brunner's used to have thin metal ID tags attached to them, and not very well either. It was quite common for them to go AWOL, which makes finding parts all that much harder

Sep 02, 2014
I See You Are In Alberta
by: Anonymous

Most of my compressor repair days were spent in Alberta, and the shop I used to work in in Red Deer used to have a lot of old Brunner parts. They were taken over by a larger company a few years ago, and I don't think they have them any more. At any rate, you can have a chat with the guys at Central Air Equipment in Red Deer and see if they can lead you to anyone who might still have some. We rarely rebuilt Brunners in most of the other places I worked, due to the lack of new spares, but they were very well built units, converted refrigeration pumps, so they tended to last a very long time. Very simple designs that rarely gave problems. One of my bosses joked that they went out of business because they never sold any replacement parts.

Sep 01, 2014
more discoveries, reeds look re-used
by: Mathew Banack op

I was mistaken about the lo-side of the pump, the intake is a reed valve, the exhaust is the disc valve.

The hi-side is as described. Both intake valves are reed-type, on the piston-side of the valve plate.

At tdc, both pistons are about 12-thou below the deck height of the cylinders.

It looks like that during the first life of the compressor, crankshaft and or wrist-pin bearings got loose, and it appears that inertia carried the pistons against the valve plate, and hammered the imprint of the seats into the reed valves.

The valve plate has what appear to be fresh surface grinding marks, and to my best straightedge, appears flat.

Both intake reed valves have imprints on them from the valve seats, on the piston-side, not the valve plate side. Those reeds would have started life perfectly flat on both sides, and during the first-life failure, got the impression of the valve seats beat into them by the pistons. Turning the beat-up reeds over works for the lo-side, but not the hi-side, the hi-side reed is just too beat up to sit flat.

At this point I have to find new reeds and new gaskets. It looks like the reeds are simply flat-cut from 10-thou spring steel shim-stock. If genuine or re-pop application specific parts are not available, I'll try to cut gaskets and reeds from stock. I'll post my results...

Sep 01, 2014
Finger Valves?
by: Mathew Banack op

I got brave and took it apart. The head cover is aluminum. The valve plate is tool steel.

The lo-side intake valve is a disc valve with a bolt in the middle, it functions properly. The lo-side exhaust valve (properly functioning) is a big flap of thin spring steel, held to the valve plate with two little rivet pins. Those rivet pins are only for assembly, once assembled the reed valve is held in place by sandwiching between the valve plate and head cover.

The hi-side intake valve is thin spring steel, held to the valve plate with two little rivet pins. It is not functioning properly, I put a rubber hose on the hi-side intake fitting, and even my decrepid old diseased lungs can suck past it.

The hi-side exhaust valve is again a thin steel reed, held to the valve plate with two bolts with springs under them and a bar across. It functions normally.

It looks like the failure is due to mis-assembly, the gasket on the bottom of the valve plate was mixed up with that hi-side intake reed, and the piston came up and hammered it and now that hi-side intake reed is messed up. There is room between the piston and the valve plate for the intake reed only, not the intake reed plus the gasket.

There are still cross-hatch marks in the bores from honing, and the pistons look new. I'm not sure how the overhauler missed a bench test, with the cooling tube off you turn it over by hand and the low-side sucks and pumps and pushes your finger off the exhaust fitting. The hi-side, while turning over by hand, the intake side sucks and then pushes, the exhaust side does nothing.

So it looks like I'm looking for a gasket set and hi-side intake valve reed.

Aug 31, 2014
Disc or Finger valves?
by: Anonymous

Actually, if this has finger valves, some people have had success making new ones out of feeler gauges.

Aug 31, 2014
Brunner pump
by: Anonymous

They've been out of business since the early 1980's. You might find some parts somewhere, but it will take some digging.

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