Margay gearbox disassembly

[philrock]

I'm trying to disassemble a Margay gearbox. There are what appear to be two dowel pins keeping the housing sections aligned - one pin at the top and one at the bottom. I tried pushing the pins out with a drift punch, hammer, and heat, but they would not budge.

Are these actually dowel pins? If so - any suggestions on how to get them out? Are they supposed to go out one direction and not the other?

If not, what are they? And how do I get them out?

[Terry Schmitz]

Phill , I just took my first gear box apart this week. I used a punch and a friend' I held up the gearbox as he hit the punch on the alignment pins. At first it wouldnt move but it finally did. as this picture shows the pins stayed in one side of the case. good luck , Terry

ackBerrypicturesIMG00369.jpg

(555.34 KiB) Downloaded 84 times

[david a luciani]

some of these boxes are a bear to disassemble.
two i have just came apart with little fiddling.
the third was big &*@!!$$ pain to split.
i oiled each one a couple of days prior with penetrating oil and that helped.
what YOU NEVER WANT TO DO IS PRY THEM APART WITH A SCREW DRIVER.
very bad things will happen .
in the end i got the stubborn one apart by working a thin steel spackle blade between the two halves.
once i worked my way around the perimeter i blasted some oil on the back of the pins. by working it closed and open with alot of patience i was able to split the cases without damage.
it was worse than some Harley cases i've split back when i played with them.

just take your time and you'll be fine.
if it gets too intense set it down till tommorow.
my 2 cents
Dave

[Rob Voska]

"if it gets too intense set it down till tommorow."

That's the best advice I have seen on here in a while. Gives ya time to think it thru, and ask questions to those with more knowledge.

[Russ Smith]

Yup...........and it also gives you time to cool down a hot temper!

[Rob Voska]

PUT THE HAMMER DOWN RUSS put the hammer down and walk away slowly! I think there's a cold beer in the back of the fridge.

[philrock]

I made a punch by cutting the threads off of a long 6 mm socket head cap screw and flattening, deburring and rounding the cut end. The custom punch plus a little extra determination did the job.

Definitely going to have to track down that Vintage Kart magazine article about this.

[philrock]

What's the deal on the 4th adapter bolt? 3 of the gearcase bolts stick out far enough to use as studs to mount the adapter. In the 4th position, there's just a hole in the case and a recess on the inside for a bolt head or a nut. I'm going to revamp and re-assemble this box and put it up for auction on ebay. What should I provide for the 4th bolt position?

I know I have to ship the unit dry, but out of curiosity, what's the correct oil to use in it?

The parts list in the Vintage Karting magazine article calls for an input oil seal for a 1.125" shaft. The part of the shaft in the seal is actually 1.086". Is this an intentional loose fit to prevent excessive heat buildup?

[philrock]

The article in the February 2008 Vintage Kart magazine lists Small o-ring: 246 and Large o-ring: 242 as parts to use in overhauling the gearbox.

First of all, the 246 o-ring is larger than the 242, so I'm thinking maybe this was a typo and the numbers should be switched. Or maybe I'm interpreting the part numbers wrong.

Secondly, these are pretty big o-rings: 4" and 4-1/2" inside diameter. I found no such o-rings when disassembling my gearbox, nor did I find any other o-rings. Anybody know what these o-rings are for?

[Mark Havery]

Phil,
The large o-rings seal the oil bath housing for the oil clutch version. The rebuild article covered the oil clutch version and not the open clutch version, that is basically the same gearbox.
Mark