semi air suspension (1 Viewer)

May 2, 2011
4
1
derbyshire
Funster No
16,234
MH
A Class
Exp
Since 2002
we have just had a semi air suspension system fitted which has improved the road handling I thought it would be good for when we use ferry.
We have had the tow ball bottom onto ramp when boarding so thought this would allow me to lift the rear to a height to clear the ramp.
After having it fitted I checked the distance it raised the rear when fully pumped up and found out it went up only 10mm which was very disappointing.
After speaking to my fitter he spoke to the manufacturer which is one of the main manufacturers they told him to alter the pump pressure from 3.5bar to 4 bar so this was done it made no difference has anyone had a similar problem if so what was the outcome.
 
Feb 24, 2013
12,980
101,084
Bolsover, Derbyshire
Funster No
24,833
MH
Hymer S800
Exp
not long enough
not what you want to hear, but ours lifts by over 100mm at rear and we regularly use it exactly as you planned to

we have a built in compressor and all controlled by keypad in cab area, how do you increase your pressure?
 

TheBig1

LIFE MEMBER
Nov 27, 2011
17,480
42,679
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
semi air, air bags dont always give a major height difference, it depends on a lot of factors. not least of which is the length of the rear overhang behind the wheels and the maximum suspension travel

the suspension type and geometry will limit what you can expect. All that semi air airbags do is firm up what is already there by replacing the bump stops

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Aug 6, 2013
11,931
16,514
Kendal, Cumbria
Funster No
27,352
MH
Le-Voyageur RX958 Pl
Exp
since 1999
Raise the pressure to the manufacturers limit - they're normally OK past 100psi / 6+bar.
 
Jul 29, 2013
9,044
17,930
Salisbury
Funster No
27,215
MH
Hymer B678DL A class
Exp
since 2011
We have semi air and it does not raise the back very much but when towing a trailer it does keep a level tow height rather than dropping with the added trailer nose weight.
 
Sep 26, 2013
4,146
5,061
Market Rasen
Funster No
28,295
MH
Self Build
Exp
Since 2003
When I replaced the spring asisters with the Dunlop kit the back end went up by 50mm before I even put any air in, and can ajust them by another 50mm with the air pressure.

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RogerThat

LIFE MEMBER
May 20, 2016
1,128
991
North West
Funster No
43,198
MH
PVC
Agreed with @TheBig1 's point about overhang length.

Ours goes up +70mm at least (at 6bar max), I drive around on 2 bar as anything higher than that and the rear end gets very bouncy!

I'd also ask, are you compressor driven (with gauges)?
 

tonka

LIFE MEMBER
Jul 2, 2008
10,776
21,396
Cannock, Staffs
Funster No
3,141
MH
A class Burstner 800
Exp
Since 2000
My Autotrail has a long rear overhang and we had it bottom a few times..
£259 kit of ebay, DIY fitted.. (y) Sorted...
I never made any measurements but it's very visible the amount of lift we now have.
 
Jan 27, 2013
1,334
871
Stamford
Funster No
24,452
MH
Benimar Mileo 282
Exp
Seven plus years
Mine suggest 2 bar in normal running but I happily put in more if fully laden or go right up to the suggest maximum of 7 bar for a little extra lift on Greek ferries.

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Oct 8, 2016
223
360
Tunbridge Wells
Funster No
45,496
MH
Bailey 75-2
Exp
I'm a newbie
I'm not an expert but I believe the gain in height when pump activated depends on what chassis you are running on. An ALKO chassis has torsion bar suspension and the vehicle when fully laden would only return to the original ride height of the unladen vehicle. The installation is different than that used on a CC or Peugeot chassis as these have leaf spring suspension and the air bellows sits on top of the spring and can raise the underside of the motorhome in relation to the axle (unlike an ALKO chassis). So more of a gain re ability to raise height if your motorhome has rear leaf springs. Both chassis types should additionally improve stability.
 

GWAYGWAY

Free Member
Sep 6, 2014
4,213
3,305
Dover
Funster No
33,216
MH
Hymer ML I 580
Exp
4 years
I have an Ebay kit on mine and it does rise a fair bit and enough for me to back into my second drive, without the air in I catch the towbar on the line of granite sets across the drive bottom. I put them up to 4.5 and it goes up about 1 1/2" more than springs alone. Make the filling fall out if I do not drop them on the road unless the garage is loaded right up.
 
Jul 23, 2012
80
82
Kingswinford & 86230
Funster No
22,100
MH
Burstner Elegance 890
Exp
Since 2012
Fitted air assist to the alko chassis on mine, raises the wheel arch by approx 100 mm - haven't measured what the back end goes up by.
I run mine ar 2 bar any more and the ride is too hard
Just a word of warning, lower the pressure before jacking the wheels up. I wanted to take the rear wheels off so pumped the system up to 6 bar to raise the chassis to make it easier to place the bottle jack underneath. As I then operated the jack handle to raise the wheels off the floor, one of the air bags blew off the lower fitting, I nearly filled my nappy!
Had to remove the lower fitting, smeared it with fairy liquid and located it over the air bag. Refitted the assy in place and re-pressurised the system, luckily no other damage done.
Dunlop system purchased from Marcel Leisure, very pleased with the result

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Minxy

LIFE MEMBER
Aug 22, 2007
32,421
65,809
E Yorks
Funster No
149
MH
Carthago Compactline
Exp
Since 1996, had Elddis/Swift/Rapido/Rimor/Chausson MHs. Autocruise/Globecar PVCs/Compactline i-138
We had AS semi-air suspension units put on the rear of a Rimor we had (7.24m) and it made quite a bit of difference to the height, before and after.

Close-up - before air-ride fitted.jpg


Close-up - after air-ride fitted.jpg
 

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