Air adjustable shock absorbers
Posted: Wed Jan 17, 2018 4:08 pm
The rear springs on my Delica have sagged (as they all do) to the point where they were sitting on the overload leaves, which makes the ride quite harsh.
I've tried adding a leaf (http://www.delica.ca/forum/viewtopic.ph ... af#p137471) which made the ride smooth again when loaded, but it also raised the rear too far when the van was empty. ("Too far" meaning it wouldn't fit through the garage door without letting all the air out of the tyres).
So I've removed the add-a-leafs and gone for an old-school solution- air adjustable shock absorbers.
Monroe MA708. (http://www.monroe.com/en-US/e-catalog/MA708/) US$70 from Amazon.
Allegedly the same compressed and extended length as my Pro-Comp 919520's (https://www.procompusa.com/eSearch.aspx ... Ntt=919520) but I think they're measuring from different points, because these clearly have a *lot* more droop than the Pro-Comps. They're also slightly longer when compressed, presumably because they have internal bump stops, but by my measurements they shouldn't bottom out (and the internal bump stops should prevent any damage if they do).
They require a touch of modification. Remove the upper pin mount (it's more difficult than it looks, but keep at it) : ...and install the bush from your old shocks (because the Monroe bush's hole is too small to fit over the Delica's mounting pin): Then you get excited and install them without taking any further photos. Sorry.
They work brilliantly so far. Just 30psi brings the rear end back up to standard height, lifting the tired springs off the overload leaves, and restores the smooth ride. With the caravan hitched up and a bunch of junk in the van it required 70psi to come back to standard ride height, and it tows without any wallow or pitching.
Monroe recommend 20-90psi continuously (so I'm well within the specs), or up to 150psi for short periods. Air shocks have a reputation for overloading the shock mount points when used on regular cars, but I figure our beefed-up 4WD mounts can handle it. (Or watch this space for a thread titled "Shock absorber mount point repair and strengthening".)
I've tried adding a leaf (http://www.delica.ca/forum/viewtopic.ph ... af#p137471) which made the ride smooth again when loaded, but it also raised the rear too far when the van was empty. ("Too far" meaning it wouldn't fit through the garage door without letting all the air out of the tyres).
So I've removed the add-a-leafs and gone for an old-school solution- air adjustable shock absorbers.
Monroe MA708. (http://www.monroe.com/en-US/e-catalog/MA708/) US$70 from Amazon.
Allegedly the same compressed and extended length as my Pro-Comp 919520's (https://www.procompusa.com/eSearch.aspx ... Ntt=919520) but I think they're measuring from different points, because these clearly have a *lot* more droop than the Pro-Comps. They're also slightly longer when compressed, presumably because they have internal bump stops, but by my measurements they shouldn't bottom out (and the internal bump stops should prevent any damage if they do).
They require a touch of modification. Remove the upper pin mount (it's more difficult than it looks, but keep at it) : ...and install the bush from your old shocks (because the Monroe bush's hole is too small to fit over the Delica's mounting pin): Then you get excited and install them without taking any further photos. Sorry.
They work brilliantly so far. Just 30psi brings the rear end back up to standard height, lifting the tired springs off the overload leaves, and restores the smooth ride. With the caravan hitched up and a bunch of junk in the van it required 70psi to come back to standard ride height, and it tows without any wallow or pitching.
Monroe recommend 20-90psi continuously (so I'm well within the specs), or up to 150psi for short periods. Air shocks have a reputation for overloading the shock mount points when used on regular cars, but I figure our beefed-up 4WD mounts can handle it. (Or watch this space for a thread titled "Shock absorber mount point repair and strengthening".)