On board compressor for air shocks.

Post by **Growlerbearnz** » Mon May 07, 2018 7:05 pm

I keep forgetting to inflate the air shocks when towing and only notice when I'm on the motorway. Also, when you get to the campsite and unhitch the caravan, it's a pain to air down the shocks for driving around, and then pump them up again when it's time to tow the 'van home.
So here's a fun little project: take a bunch of air fittings and a cheap(ish) 12V compressor, and build an onboard air system for the air shocks. Monroe's awful fittings didn't make it easy, but I got there in the end.

A bunch of random parts from the pneumatic fittings box. Compressor for inflating the shocks, a solenoid valve for deflating. But first, build a box to mount it all in.

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Folding stainless is a pain when you have the world's worst sheet metal folder.

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Peeling the plastic protective sheet off is the best bit.

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All the bits installed in the case, along with some sound deadener because that case was super resonant.

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Installed above the gearbox crossmember where it's dry.

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An outlet for pumping up tyres, if needed. The air shocks act as an air tank.

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Now the tricky part. Monroe shocks have this stupid, cheap, proprietary connector.

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Beneath the stupid Monroe fitting is a 7/16" - 20 thread. Almost an AN or JIC fitting, but without the tapered seat to form an airtight seal. Still, I can make an adapter that'll screw on.

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Adapters made from a chunk of aluminium. 7/16" - 20 threads on one end, a more normal air line thread of 1/8NPT on the other (with 4mm push-in fitting installed)

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Adapters installed. Threads sealed with anaerobic thread sealant.

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Dashboard control- a modified tailgate lock/unlock switch and a moderately accurate pressure gauge. Green is 20-90psi, the range the shocks are happy with for long-term use. They'll go to 150psi for short periods.

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Now I can do the lowrider hopping up and down thing- as long as you film it on timelapse. It takes about 30 seconds to go from 20 to 90psi.

lrp374 · Post by **lrp374** » Mon May 07, 2018 7:41 pm

Just when I thought you'd run out of projects!!

Post by **Growlerbearnz** » Mon May 07, 2018 10:55 pm

Never finished. While I had the dashboard apart I also modified the wiring loom so the tailgate locks and unlocks with all the other doors, the park lights come on when the ignition is on (as Daytime Running Lights), the horn runs through a relay (so I can add an air horn later), and my lambda/O2 gauge turns on with the ignition rather than with accessories (it wastes a lot of power if the engine's not running).

Oh and tightened one of the pivot bolts on the steering column adjust mechanism, that was causing a vague feeling in the steering by letting the steering wheel move ever so slightly. Whee!

The next job is to repair and paint the tailgate, which has a touch of rust starting behind the windscreen rubber. But of course I'm not going to just fix it, I'm going to modify it to suit my swing-out tyre carrier (delete the numberplate recess) and stiffen it internally (I dislike how flexible the standard tailgate is). I have a spare tailgate stored... somewhere...

lrp374 · Post by **lrp374** » Tue Dec 17, 2019 5:37 pm

Growler I've got a question on the threads used on the shock. You've made a block with 7/8" x 20 tpi threads on one end and 1/8" NPT on the other. What are these tpi threads and would a tap for that be easy to find in Canada? I'd like to use something more standard if I add a compressor later.
Thanks
Larry

Post by **Growlerbearnz** » Sat Dec 21, 2019 1:46 pm

Whoops! They're 7/16" diameter, 20 Threads Per Inch (tpi). (Not 7/8" diameter, which would be huge! Editing the post now...)

A 7/16-20 tap is easy to find, it's a pretty standard imperial size for bolts and nuts, it's just an unusual thread size for air lines.

It looks like you can just buy adapters, like these:
https://www.ebay.com/itm/Monroe-Air-Sho ... 3293426978

lrp374 · Post by **lrp374** » Sun Dec 22, 2019 10:03 am

I took one of the plastic nuts to CT and used their bolt board to figure out what happened. Didn't help much as 7/16 is not a very common size. The EBay item looks like it could save quite a bit of work or looking. Thanks for the help!!

M.hutt · Post by **M.hutt** » Thu Apr 16, 2020 11:45 pm

Growlerbearnz wrote: ↑Mon May 07, 2018 10:55 pm Never finished. While I had the dashboard apart I also modified the wiring loom so the tailgate locks and unlocks with all the other doors, the park lights come on when the ignition is on (as Daytime Running Lights), the horn runs through a relay (so I can add an air horn later), and my lambda/O2 gauge turns on with the ignition rather than with accessories (it wastes a lot of power if the engine's not running).

Any chance we'll see a walkthrough on how to do these specific mods!? These are exactly what I'd love to do!

Cheers!