# Help Needed! Air Lift MK4 Slam XL's different pressures



## Ayzed (Jun 1, 2012)

First post so be gentle! 

I've just finished my Air Lift install on my MK1 TT with MK4 Slam XL's with fully manual controls; When Air'ing up the front struts the front driver's side bag holds more pressure than the passenger's side bag to achieve equal ride height. This is off by about 15-20psi. When fully aired out the passenger side bag will drop to 0psi and the Driver's side 5-10psi approx as its not notched yet so I don't think it's the gauge at fault. 

Any body got any ideas? It's bugging the hell out of me and as the pressure is different at the fronts the car is driving slightly erratically in the bends which isn't much fun! 

Any help appreciated!


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## Ayzed (Jun 1, 2012)

Just to add more detail to my set up... 

Im running a 4 way system from manual paddle valves with the lines run from the tank at the rear through the centre tunnel to the switches. The lines then run to the guages and then to the bags. 

For the front pair, the lines go though the passenger side slam pannel and across the top of the pannel over to the drivers side; therefore about 1.5m longer. Will the added hose length make any difference to the pressure? 

Also I will be notching the chassis in a week or so's time; will that have any effect on it? (im not sure if it will but i've been told buy Luke at Plush, the UK distributor of Air Lift) that it might... 

He also said that this isn't unusual to have different psi's due to the weight distribution in the engine bay; is this correct? as for me to match the ride height at its lowest drivable position im 35psi left and 50psi right. Surely there must be something wrong! :banghead:


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## plastic_bullet (Mar 11, 2006)

It doesn't seem right at all. The first thing I would do, is check to see if the struts are full seated in the steering knuckles.


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## VR6OOM (Nov 8, 2002)

Also, how much extra line are you using for one side? They should have been the same length or dang close.


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## Ayzed (Jun 1, 2012)

There's about 1.5m extra hose to the drivers side front bag; so would this cause the added pressure? I thought as it was pressurised it wouldnt make any difference how long the hose length is (of course it would over a long distance but surely not that far? ) 

As far ias i can tell the struts are fitted correctly so I don't think one is sitting lower than the other. 

Thanks for the responses guys, its much appreciated!


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## GolfL (Apr 7, 2012)

i also have the same "issue" 

Bagged my MKV 2/3 weeks ago. Also my passagers side bag has +- 1~1.5M more line (line is running from trunk-> inside car-> gas pedal hole-> underneath window cover-> passager side). 

Also got the same thing as you. If i fill the bag with 4 bar at driver side, and 4bar at passager. Passager side is higher in height then driver side, about 1 cm higher. To level my front i have to differ the pressure about 0.5 bar. So 4 bar left, 3.5~ right. 

Strange thing is that my rear has the same.... Also passager side is higher with the same pressures in the bag. But there my lines are about the same lenght..... 

Front bags: Airlift slam XL 
Rear bags: Bagyard classics


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## plastic_bullet (Mar 11, 2006)

Why would line length make any difference... its still the same pressure... over a couple feet im sure there is no change, over hundreds of feet on the other hand...


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## GolfL (Apr 7, 2012)

@plastic_bullet, 

That is also what i thought. But cant get any other explanation... 

Do you guys drive with the same pressure FR-FL and RR-RL then ?


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## Wastegate13 (May 3, 2006)

Are you guys noticing this while sitting in the car? Weight compresses the springs, which makes the pressure reading go up. You'll notice the same thing taking corners, the outside bags will go up in pressure as the weight transfers. My fronts are within a few psi with me sitting in the car, I'm a smaller person, but my rears are way off. I recently replaced my drivers rear bag so I'm thinking it hasn't been "broken in" like the passenger bag so it builds more pressure at the same height by about 15-20 psi depending on load in the car.


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## Ayzed (Jun 1, 2012)

What I've been doing is airing up so that the front arch gaps match whilst in the car before pulling off. This is where the difference in psi is; when stationary. Obviously when driving the gauges move dependant on road surface and cornering. 

I've ordered more hose and am going to extend the passenger side with 1.5m so the fronts both match; hopefully this might alleviate the problem and also mean there is higher pressure for both front bags instead of reducing the pressure in the front drivers side by relocating the hose. (will this make the front 'stiffer' buy having a higher psi?) 

Maybe this will work, but i'll keep you all posted. If not then i have no idea :screwy:


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## [email protected] (Feb 19, 2010)

plastic_bullet said:


> It doesn't seem right at all. The first thing I would do, is check to see if the struts are full seated in the steering knuckles.


I think this guy has the right idea. 

Could you snap a photo of how the struts are seated into the knuckles on both sides?


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## Ayzed (Jun 1, 2012)

I'll try and get a snap this weekend when I test fit the wheels. So is pressure and hose length not the problem for sure then?


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## [email protected] (Feb 19, 2010)

Ayzed said:


> I'll try and get a snap this weekend when I test fit the wheels. So is pressure and hose length not the problem for sure then?


Yeah, it's definitely not a hose length issue.


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## GolfL (Apr 7, 2012)

I am 100% sure that my strut correctly mounted.

In my situation when i air out front, both sides are deflating to 0 bar. So no pressure is "hanging" in my struts.

Not like TS that 1 side is still having pressure when aired out.


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## Miotke (May 16, 2010)

[email protected] said:


> Yeah, it's definitely not a hose length issue.


This.
Length will only affect fill rates, once might fill faster or slow than the other.

I would bet that the strut is sitting lower in the knuckle that won't reach 0 PSI.

Look at both very carefully and try to get them exact and this will solve your issue. :thumbup:


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## Ayzed (Jun 1, 2012)

At the moment it's the drivers side that wont reach 0psi but that is due to it sitting on the driveshaft as I haven't C notched it yet. 

At ride height the passenger side sits at 35psi and the drivers side 50psi. Im guessing as the P/S needs less psi to achieve clearance it's this side that isnt sitting correctly? 

So is it the passenger side that would not be sitting in the knuckle correctly and not the drivers side? (sorry for the noob and very obvious answer to my question)


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## GolfL (Apr 7, 2012)

Even if it isnt notched it should reach 0psi. Only the car should be not level if you look from the front.

When i air out everything is 0psi. 

When i drive the driverside bags are about 10~psi higher then passager side. Otherwise i am not driving level (in height).


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## Miotke (May 16, 2010)

GolfL said:


> Even if it isnt notched it should reach 0psi. Only the car should be not level if you look from the front.
> 
> When i air out everything is 0psi.
> 
> When i drive the driverside bags are about 10~psi higher then passager side. Otherwise i am not driving level (in height).


This is correct. I just finished my fronts before Wuste last weekend and I air out at 0PSI. 
The only thing I've done is disconnect the front sway bar and removed the end links for them completely the sway bar is still installed just doesn't do anything but hold me up, have you done this?(sorry if you already stated so).

Also what's the word on if the struts sit in the knuckle evenly?

Curious and I want to help resolve this issue.


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