Hewland MK. 9 leak stop

[CornerSpeed]

Hey there, everyone,

Like a lot of you, my RF79 came equipped with a Hewland Mk. 9. And as they seem prone to, mine had a small but annoying leak where the shift selector “hockey stick’ exits the bearing carrier to be bolted to the shift linkage. No problem, I figured. I’ll just buy and install one of those nifty seal kits from Pegasus. I did that and the leak was contained. I was thrilled! Then I went to my next event and discovered the seal kit prevented my transmission from being able to select half its ratios (2nd and 4th). I removed the seal kit to get through the weekend and endured the return of the leak.

My hockey stick only has one hole in it so there is no adjustability there. And the “handle’ tapers down past the one mounting hole so it’s too thin at the end to drill another hole. I only see two solutions. One: machining down the bearing carrier (and the brass bushing inside) the thickness of the seal kit ring to open the gap. But machining the bearing carrier will remove the mounting flange moulded into the bearing carrier, into which the seal kit is tapped and threaded for mounting. Option two: Does anyone make a longer shift selector fork with multiple shift linkage mounting holes in it?

Anyway, throwing this up for consideration by those of you who also purchased the Pegasus kit and then had to re-engineer it to make it work and your transmission shift properly. Any other solutions out there that I’m not seeing that will let me re-install the seal kit and still have four forward speeds?

Thanks!

[Lotus7]

Try Scott Young https://www.facebook.com/scott.young.100

[scorp997]

My shop adds an o-ring in between the two bushings of the hockey stick. Not very large and can be a bitch to get the hockey stick back on (don’t pull it out for gear changes).. works pretty well and doesn’t add any length to the outside of the box.

[pooch776]

Another easy/cheap solution that I have successfully used when there is not enough room to install the Pegasus seal is as follows: Drill a hole in the side of the bearing carrier between the two bushings. Tap the hole and install a zerk fitting (make sure the fitting does not contact the hockey stick). Then pump the cavity full of grease. This will create an oil tight seal between the shaft and bearing carrier. You will need to add a little more grease after every race weekend to maintain the oil seal.

Cheers, Joe

[teamwisconsin]

Michael-
There are a handful of solutions (in addition to the excellent solution of an internal o-ring groove that John mentions). Traditionally, I just toss the carrier on the mill and counterbore the carrier for a seal, then press one in place. No bolt-on seal kits needed. Secondly, we have on occasion also successfully performed "hockey stick enlargement surgery" (ahem) whereby we machine an additional length to the end of the hockey stick, machine off the end of the hockey stick with the hole in it, then weld the extension in place and machine/dress the whole shebang back to nominal size giving you the additional length to drill a new hole in a different location.

Or, you can always just buy a new hockey stick.

Hope this helps-

[Tim.R]

The first way Ethan described - get it machined for an „two lipped“ oil seal (don’t know the real word) and press one in.
Completely dry and can be changed easily if necessary.

it cash be machined with everything except the gears in it.


Tim

[bob darcey]

The "real word" is "double lip, no spring". Dimensions are .625" ID, .875"OD, .093" depth.

[Hawke]

And yet another solution. When you do your ratio change for the next meeting, coat the hockey stick with your sealant of choice. Hylomar works the best. At least it will not leak till your next meeting.

[kea]

We have been machining the carrier and installing a seal, much like the FT200 and LD200 uses, since 1983. Clears any shift joint issues.

[Steve Davis]

You said the hole in the shaft leaves no adjustability. Don't know if it would help, but my Vee came with a CLAMP on the shaft (https://www.mcmaster.com/shaft-clamp...-diameter~5-8/). Shaft dia might be different, but the clamp provides infinite adjustment .. only problem being .. getting it back where you want it each time. I marked the shaft with some 'zizzwheel spots' to get it pretty close. Mine holds the shaft like a weld .. at least so far .

Also .. for the leak. I have many times used a simple paper towel - folded and wrapped around the shaft with a ZIP TIE(s) to hold it to the shaft/housing. Doesn't STOP the leak, but limits the mess and is easy to replace as often as necessary. Just need to check the lube level based on the size of the leak.

Steve, FV80

[TimH]

Also .. for the leak. I have many times used a simple paper towel - folded and wrapped around the shaft with a ZIP TIE(s) to hold it to the shaft/housing. Doesn't STOP the leak, but limits the mess and is easy to replace as often as necessary. Just need to check the lube level based on the size of the leak.

I've had to put a diaper on my MKs a few times. Never bothered with the zip tie because I took the diaper off while running because the drip never amounted to much.

[CornerSpeed]

Hey everyone,

Thanks for all the input on my Mk. 9 transmission ‘hockey stick’ leak issue. I decided to have it fixed permanently (well, at least as long as the installed seal lasts) and had the bearing carrier machined by Ethan Shippert, who then installed the proper double-lipped spring-free seal into the carrier. Glad I took this approach as Ethan found other issues that may have been contributing to the leak and he repaired those issues too. Leak stopped! Thanks, Ethan!