Cat 12g. 3wc 1518 Looking for a part number for the air pressure switches mounted on the treddle valve Dealer cant find them on SIS. Can get non gen but prefer to use OEM. What pressure should the warning come on and off? Warning comes on around 95psi and pump unloads at around 110psi. Also got a air leak on RH tandem when brake applied. Could i get the procedure and parts breakdown for the brake / spindle assembly.
They're right there in SIS. 9G8009.
Amazing that members here can find stuff literally in minutes that dealers allegedly can’t. From memory the compressor cut-off pressure should be something like 130psi. Sounds as though yours is a bit on the low side. EDIT: The governor settings are - cut-in 110psi. Cut-out 135 +/- 5 psi. First suggestion would be to make sure the governor is working correctly because they can get gunked up inside, especially if the compressor is a bit worn.
I reckon thats my problem. Ill replace the unloader valve and see if the alarm will stop squealing at me when i brake.
Post covid, everything just seams to hard. Standard response from the young ladys who work in parts is, “whats your email address and tick the parts you want off the list”
Do you call the governor (photo below) the unloader.? They are adjustable. I think I would pull it apart first and have a sticky beak inside it. https://sgi.sk.ca/documents/37148/138136/page_17_image_02.gif/ff7d79eb-8a3f-4626-83c0-052fe06fd7f7?t=1483118864000
Mine was all gunked up inside the compressor head. There is a plug that has a spring and a little piston underneath.
There’s a brake chamber and a valve in the right rear tandem area behind the frame. I had two leaks there. Not easy to get at.
just a thought have the air tanks been drained they fill up with oily gunk . have been on graders and a couple of pumps on the brakes and low air warning is going off, drained the air tanks and heaps of crap in them hadnt been drained in a long time. the more crap in the tanks the less air reserve.
Here's the SysOp for the Air System, plus a few other nuggets. The D&A procedure says it suits 12G from S/N 3WC1087-up
Drain daily. A lot moisture around at the moment. Get a bit of oil from wet tank as well. Not enough to warrant a new compressor yet.
Thankyou Nige. Exactly what i was looking for.
Ok next one, looking for the grease nipples on the unis on the drive shaft between the engine and pumo. Its about a inch long and narrow.
This was the same shaft on our 12G a few years ago. Was still working fine and not making any noise, only pulled it apart to replace the a/c belt. The uni joints are “lube for life”.
Not serviced separately as far as I can see.
Yeah its looking that way. I brought a nipple a few years ago from cat. Ill have to look through the old invoices for the number. Maybe they got it off another s/n. Definitely has grease nipples on them. But it has a habit of breaking them off. The clearance is tight. That why i got genuine last time. The unis have probably been replaced a couple of times in its 20,000hrs.
I was searching for the grease nipple based on the part number of the universal joint. It should be listed somewhere but isn't. Found this though.......... Description of Change: New bearings are available for the pump drive shaft universal joint on the above machines. The new sealed bearings do not need lubrication. Formerly, access to the lubrication fitting was difficult. It was possible to damage the fitting when lubricant was put into the bearing. Adaptable To: The new 5T1362 Bearing is a direct replacement for the former 8D537 Bearing Assembly. So if you have the forner universal joint part number installed then it has been updated. The grease fitting for the 8D0537 unversal joint is 8D0538.
Thanks Nige yet again. That looks like the correct one.
Also gave the governor valve half a turn out and set it to 135psi. Will give her a run tomorrow once i pull the seat and HVAC fan out to work out why it’s blowing the fuse. Dont have any glass fuses left (joys of living in the scrub) so going to make a circuit breaker to fit in fuse holder. Just never ends. (.22 magnum shells are just about the perfect size. My guess is 50,000 amp fuse)
Let us know what you find. Could be just a 12G thing, ours does the same. Usually get at least several big days out of a fuse, longer on lower fan speeds.
Forward vents fan had come loose and stalled the fan motor. Also the fan resistor was loose. Low speed wire had come off resistor. And wiring loom had rubbed where the passed into evap box as the grommet had perished.