Height Control & TV Antennas

[Page Britt]

Glenn,

The procedure outlined in the Ridewell documentation the blue box is undoubtedly the best way to set it up from scratch or of more than on height control valve is changed at a time. Since I only had to change one (left rear) and the ride height seemed about right before than valve failed I utilized a somewhat abbreviated procedure. I'm not fortunate enough to have pit so when I changed the valve (as I do whenever I have to get under the bus with it elevated) I raised the rear sufficiently with the leveling jacks, dumped the suspension, securely blocked the bus under the frame at the crossmember close to the oil pan. I have a couple of big sound hardwood blocks cut from a 12x12 or perhaps even bigger timber and some smaller ones cut from sound cross ties. I then bled the air out of the tanks before cracking open the air lines at the valve. Removed, moved fittings from old to new, reinstalled. I thought I was being clever by simply disconnecting the linkage to the valve control arm at the arm thereby preserving the adjustment that was previously set. After I let it down and aired it up I discovered that didn't matter due to the fact there is an angle adjustment you can make on the control arm at the valve of 20 degrees or so (I set mine dead in the middle). The old one was apparently set a bit different plus I'm sure there is some variation in tolerances between individual valves. Anyway as to how I set it - I used the dimensions given in my documentation from ground to top of frame, I believe it was 37" front and 38" rear but the documentation is out in the coach. The PT-40 (and probably many of the rest) have 10" frame rails so in my case as long as I'm sure I'm measuring to the bottom of the actual frame I can simply knock 10" over the specified measurement. It is possible (at least for me) on a PT to skinny in between the drive and tag wheels and bend around / scoot forward a little and adjust the valve linkage with the suspension dumped without having to raise and block the coach. I wouldn't recommend this for anyone that has any claustrophobic tendencies but if you have it on level ground, dumped, chocked the leveling jack controls in retract position and the level maser system safed (off) it strikes me as being not really unduly dangerous. I have rather long arms and have worked in some pretty tight places in the past so that helps. Anyway I checked the rear heights (make sure the tag is dumped) and the right was real close, the left about 1.5" low. I dumped it, shut down, scooted under and lengthened the left rear linkage between the valve control arm and axle by about 3/4". Started the engine, aired it up and checked (which you can do without really getting anything but a long arm under held right down at ground level with the tape measure going up to the frame bottom) it was about 3/4" higher. I therefor conclude that the relationship between change in linkage dimension and ride height is roughly linear (make sense when you think about it). Repeat process lengthening the linkage another 1/2" or so. I check and have another 1/2" of ride height on that side. Lengthen another 1/4" to 1/2" and upon airing up and checking find it within 1/4" of spec and only 1/4" variation side to side. Pulled it up the most level part of our driveway and rechecked same result and front is similarly close to spec. Visually looks like the same gap between the tire and wheel well as I had before the valve failure. I'm happy, Lynda & Lady Bird seem happy.

--Page

Page & Lynda

1984 PT-40 "Lady Bird"

Tallahassee, FL

On Oct 6, 2009, at 10:27 PM, ragster_ga wrote:

Page,

I would be interested to hear your process for the height control valve adjustment. I believe mine needs a little tuning, but have not tackled the project yet. What measurement did you use for your settings and where did you measure? Did you deflate all the bags and then inflate one at a time to get the setting? Were yo fortunate enough to have a pit or did you block it up enough to go under but still cycle the valves?

Thanks for your insights.

Glenn