Pressurizing GPA Axles???

[Steve Greenberg]

Hello,
Happy New Year to All :D
Have any of you guys pressurized the diffs on your GPA to keep water out? I never did this to my GPA or DUKW. I have a friend who asked me about doing this on a GPA. If anyone has some instructions or photos of how to do this in a GPA I would appreciate hearing from you so I can pass the info on to my friend.
Happy New Year,
Steve 8)

[GlennV]

Hi Steve,

i don't think this is a big problem. If you take a small 12Volt compressor with a small tank and a pressurevalve, you can use the ventilation lines that run from the inside of the tub to the axles to put a small amount of pressure on the axles. Just a little pressure should be enough ......

Cheers,
Glenn

[fordgpa]

Hi Steve I agree with Glenn ,but in australia they use it i got a picture from John Wilson he has done it on a GPA zee the picture.
His email is jdwwilson@bigpond.com
Peter

[Steve Greenberg]

Glenn & Peter,
Thanks for your replies. I will pass them on to my friend.
Thanks,
Steve 8)

[John Vetter]

Hi all,

For the axle air system was wondering what operating pressure was used (1-2lbs?) and what leakage rate people had experienced. Does a prefilled tank sound possible with high pressure and regulator to allow use for a reasonable period of time?
I noticed that the V100 armored car uses a similar system with the air lines running to the steering knuckle so that the rubber boot inflates a little!

Thanks,
John

[John Wilson]

G'day Fellows,
John Wilson here. Re your differential pressurization questions. I have fitted 2 GPA's with this system and they both work a treat. The compressor is sourced from a "differential air locker" installation kit. The compressor has a mini air tank and also includes a pressure switch that is set to cut out at around 125psi and cut in at 75psi. To this compressor I have attached a small mini air pressure regulator that operates in the range of 0-15psi. I set the system to run at around 4psi. The secret to this installation is to make sure that all hubs seals etc and sealing surfaces are in good condition. In addition I trashed the old original front axle wiper seals and fitted a set of good quality CJ wiper seals. The pipework is all flexalbe oil and gas resistant 1/4" ID rubber hose. The hoses run through the hull via the inside RH chassis rail and exit the hull where the old differential vent hoses were located. On the differential housings themselves I ran flexiable rubber hose to all diff chambers(3 on the rear and 5 on the front) so as the internals of the diff can be pressurized evenly without the risk of oil transfer from one chamber to the other. When the compressor is in operation, it takes about 20 seconds to run up and pressurize the system and then the compressor automatically cuts in and out about for about 5 seconds every 30 seconds to a minute to top up the system. If the compressor runs continually then you have a leak and with a GPA its very easy to diagnose. Just drive into water and voila, you will find you air leak. All up, parts cost to install, about $500AUD (about $375USD). Hope this helps. I mounted the compressor in the passenger side air tunnel so as the driver can see the pressure gauge to monitor the system. One last thing I took the liberty of fitting a small green running lamp to the system as GPA owners would well know, its very hard to here a small compressor running when you are "Roaring" along in a GPA. Finally dont forget to switch your compressor on before hitting the water as !!!!!!!!!!!!!!.
Good luck with your decision
Kind regards
John Wilson