Herky Jerky 2008 Precedent

[trigger1937]

erict,...Glad to hear there is an upper plug. This should solve the problem of adding the oil. I'm so old I remeber when cars had things like a coil, distributor, rotor, etc. and things like a 2 barrel carburator. Heck,..my first car was a 1939 Ford 2 Dr sedan with running boards. It had a Flat head Mercury V8 engine. Boy was I hot stuff.

[Seastar]

Same first car, 39 Merc flathead 8. Wish I still had it.

[Colbyntx]

Originally Posted by trigger1937

Wow,... Thanks for all the information. I've messed with an MCOR or Petal pot before and they are a &*%$# to get out. How well are they sealed, as I know they are pretty tight and the only input is a Stainless Steel shaft through a tight bushing. This would not be a two hour job.

On the issue of draining out the oil,.. in most rear ends the plug is just a few inches above absolute bottom and it is easy to get the oil out,..but to put it back it usually take a gun under some kind of pressure. You can't just pour the oil ink. what do you recommend.

Trigger,

It is like filling the lower unit in a boat motor. Take out the fill, take out the drain plug and let it run out. Put in the drain plug and fill it back up until it comes back out the fill hole. You can use a pump oiler, big syringe, lower unit oil pump or what ever. As Shadowman said, it could be your motor but I bet the oil has never been changed and it will be good to change it. If you need a new MCOR, lvssales.com is the cheapest place I have ever found.

[basshawk84]

I had similar issues with my 05 Precedent and the MCOR ended up taking care of it. The least expensive place I found it was at www.cartbarn.com.

[trigger1937]

Seastar,...Those were the good old days,... when all you need was one "Quarter" to buy enough gas to take your girl and cruse around town. Mine was a 48 Merc flat head.

Anyway,..about the MCOR,... Is it totally sealed or is it possible to take it apart and clean the guts. Is it just a Potentiometer inside or some other electronics. If I remember correct, I was taking the entire foot/Brake pedal assembly out of the chassis so I could wire the brake switch and build and attach a Park switch on the unit. To do this I had to unplug the two cables to the MCOR unit. The connections were very dirty and difficult to clean. I was not getting any of the Herky-Gerky speed issues before I took it out. I did not touch the MCOR, just unplugged it. I think I will have to take it out again and see if one of the pins are making a bad connection. However,... thinking about the way the speed is Herky-Gerky,... it is too symetrical. The speed seems to pulse at exactly the same revolution. It is not intermittant like a bad electrical connection. So when I drive it at VERY SLOW speed, it is like I get a pulse of power on each full revolution of the tires or something near that. When I speed up to half speed, I still get the pulses but much faster. That is NOT a bad electrical connection.??????

[Stevegrmich]

MCOR appears to be a sealed unit, ie, glued/sonic welded together . . .

[basshawk84]

Yep, it is a sealed unit.

[shadowman]

they are not 100% waterproof...............supposed to be but arn,t......plenty of members have opened one up to find water or grit or what have you..............................

[basshawk84]

Yep, the one I replaced earlier this year had a warped case. Instructions came with it to drill some vent/drain holes in the plastic box that surrounds the Accelerator/Brake assembly as well.

[Stevegrmich]

Originally Posted by shadowman

they are not 100% waterproof...............supposed to be but arn,t......plenty of members have opened one up to find water or grit or what have you..............................

My guess is that where the MCOR shaft enters the assy is where junk can get in . . .