Help in diagnosing an oil leak...

Post here if you require help or have information that may assist others with their MX-5.

Re: Help in diagnosing an oil leak...

Postby mgrays » Fri Apr 08, 2016 1:56 pm

I would break the exhaust in front of the cat and drop the rest as one part.. then just 2 bolts and 3 rubbers . plus the rear subframe brace which is 6 easy bolts (well by now only 2 will be...).. and you can easily replace the cat bolts if you have to break/cut them .. guess would be two M14 x 30mm bolts + nuts off the top of my head. I half think you might get away with leaving it in place but it would be a right pain.

Tip is to tip the whole engine around the engine mounts by putting the car jack under the front of the sump (with a bit of wood to spread the load) when you have the rear gearbox mount off.. it helps a lot getting the top bellhousing bolts off.. I use about 1m of extention bar on a 1/2" socket with a wobble end to do it.. maybe longer when I use torque wrench to do them up again

another tip.. if you use black moly grease.. you will over torque the bolts at the factory torque settings..
another tip.. remove the gearchange shaft from inside the cabin while you are still clean at the start of the job .. need to remove the central console to do that.
Use the cup of the trolley jack to hold the gearbox .. if you have a full sized one.. still will need to drop it off the trolley jack to drag gearbox out as it will be too tall on top to clear underside of car.
Make sure the fill port on the gearbox will come undone.. it is an NPT thread so needs thread sealant on it.
Align the clutch plate with the pressure plate before you tighten the clutch cover plate up.. then no need for fancy alignment sticks.
Clutch plate has to be the right way around .. so look before you remove it..

No need to drain the oil but it will come out the prop shaft.. I stuck a small aerosol cap on.

I have done gearbox input shafts.. but really unlikely to be an issue as it is above the oil level. Think the nose housing unbolts and it is pretty easy .. but then officially you need a gasket for the nose of the gearbox... instant gasket/blue hylomar will do.

I have done it a couple of times with the car on 4 axle stands.. you can do it with 2 but need to get under the back end for dropping the exhaust .. and the oil will come out as you pull the prop if you only
have it up at the front.

Did not have any special tools to do the seals.. but do give the steel running surface of the crank a wipe over with WD40 and 1000 wet and dry.. this will smooth off any lacquer/deposits so the oil seal can bed in properly.

Done at least 3 gearboxes on a Mk1 now. One clutch. Still have stock flywheel but I did reface it (fancy clutch material)
If the rear crank seal has gone.. likely the front one and the cam seals are on way out (they all age at the same speed) .. plus the cam sensor O ring..
Malcolm GS
94 JLtd2 FM2
Posts: 665
Joined: Mon Jul 19, 2004 7:03 pm
Location: Aberdeen, Scotland


Return to Technical

Who is online

Users browsing this forum: No registered users and 5 guests