BW35 gearbox Pressure gauge thread

keynsham1

keynsham1

Active Member
I have tried to set my kickdown cable by trial and error but I am not sure it is really in the right place so I want to set it using a pressure gauge as per the manual. There is a threaded bung at the back of the gearbox to screw an adaptor in but I don't know what thread size it is. Does anyone know what it is?
 
I've had a look in the parts book and it says- pipe plug 1/8, so I googled that and it brought up

NPT - American Standard Pipe Thread Taper

Pipe Size (inches) 1/8"

TPI 27


Nominal Outside Diameter Pipe OD (inches) 0.405.

Make of that what you will.
 
I have to say that I have never had the need to use the pressure guage, I always set them on the road, but failing that I would remove the sump and set it that way. The result is going to be the same.
 
It seems to me that there is a sweet point just between when the cable is too long and too short. One way it hangs on to the gears too long and the other way it gets clunky. I can't remember which way around it is. The problem I have is that as my car is a NADA it is a real bugger to get to the cable and adjust it repeatedly during road testing. At least with the gauge I will know it is right. I probably still won't be happy with it mind you but that's another story!!!
 
Removing the sump is not very inviting either as I still have the NADA filler neck on the side of the sump rather than a dipstick tube and refilling the box is challenging at the best of times. I'm not keen on doing that again in a hurry! I am sure Rover or I should say Borg Warner could have made this easier!!
 
The plug may be tight if it is sealed with a Loctite produc, most likely a hydraulic thread sealant should be used, but may workshops use the standard bottle of thread loc
 
So I have bought a pressure gauge kit with the correct fitting to check my gearbox pressure to set the kickdown cable. But I have noticed a leak which seems to be from the rear edge of the sump gasket. This could be a blessing in disguise as If I drain out the oil and remove the sump then I can remove and reseal the plastic filler neck (NADA) and also have a fighting chance of getting the 1/8" NPT bung out to fit the pressure gauge. So on th my next question and it is about sump gaskets. From what I can see I have some choices, which are basically cork, composite, rubber or silicone resin.

Anyone have a preference??

OIL SUMP PAN GASKET BW35 AUTO [CORK] - Rover P6 Parts supplied by Mark & Angie Gray (roverp6cars.com)

OIL SUMP PAN GASKET BW35 AUTO [COMPOSITE] - Rover P6 Parts supplied by Mark & Angie Gray (roverp6cars.com)

Now Available Borg Warner 35 Automatic Gearbox New Rubber Sump Gaskets | eBay

Custom Borg Warner BW35 Silicone Resin Auto Gearbox SUMP GASKET NEW | eBay

There is then the question of gasket sealer or no gasket sealer???
 
And from what was said above, I guess checking the position of the cam would make more sense if I am in there already?:):):)
 
Oddly the method for setting the cam is in the Rover manual, but doesn't appear in the official BW service and rebuild manual I have! That just gives cable adjustment at the throttle end and pressure setting with a gauge. Also oddly is that the method for setting with a gauge differs from what is stated in the Rover manual. The BW manual stated to set the cable for a pressure of 50-75PSI at 700RPM in 'D' as opposed to 90-105PSI at 1000RPM in 'D'. I guess if one is right the other has to be!! The tolerances are huge!!!
 
keynsham1 said:
The BW manual stated to set the cable for a pressure of 50-75PSI at 700RPM in 'D' as opposed to 90-105PSI at 1000RPM in 'D'. I guess if one is right the other has to be!!
Click to expand...

I think you'll find it is both, it has to be (using your figures) between 50-75PSI at idle (nominally 700rpm), then you increase the rpm to 1000 and you should read between 90-105PSI.
 
I does make perfect sense. I plan to set the cam when the sump is off and then check both revs readings with a gauge, just for the sake of it!!
 
keynsham1 said:
I plan to set the cam when the sump is off and then check both revs readings with a gauge, just for the sake of it!!
Click to expand...

Use the gauge, I've never heard such a thing! I've got one, it's like brand new, I've never used it, and I don't think the bloke I got it from ever did either. The hose is still lovely and clean with the date stamp all the way along it. It would be a shame to use it now and risk getting it all dirty....
 
So I have the sump off of my gearbox and I am looking at the cam setting. It is not really clear from the manual where the setting should be at full throttle pedal movement. The picture attached is when the throttle pedal is fully depressed to the floor! In the manual it looks like the valve should align with the hole but mine goes too far. Oddly though the cable is quite slack when no throttle is applied but to make the valve move I would have to shorten the outer cable. Does this sound about right?? Any help please!!!20210630_121250.jpg
 
The cam should be resting against the valve with no slack at rest, and if all the linkage is as it should be then full throttle and kickdown settings will be where they should be as well.
 
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