Was browsing the service manual as my front air struts are within the "replace date range" in the TSB on front suspension air leaks -- and am I correct in saying that the air suspension Defender does *not* need to be re-aligned / need an alignment after replacing front air struts? I was surprised is not part of the step by step instructions... so guessing answer is "no" ?

(full disclosure - this front suspension is different than anything I've ever seen)

I was curious since I've had it realigned for 1.5" lift rods, and wondering if I need to explain that to the dealer. If not needed, I'll leave out the "lift rod" detail.

 

I'm not an expert, but i'll explain the logic of what I think is the answer of No. I have done some reading on, and have experienced other air suspensions. Far as I understand they're all fairly similar.

The air system isn't really a 'strut' so to speak, it's more a bag of air that is inflated/deflated to raise/lower the chassis on its existing suspension. It doesn't change the geometry of the suspension when you go up/down just the clearance.

So that's why when you replaced the lift rods it needed one, but if you replace the air bladders you won't. As they are just 'up' and 'down'


might help visualize it some, that's where I got the details to make me think that way.

 

As long as the alignment is within specs before the work is performed, there is no need for an alignment after replacing air struts. Now if aggressive tactics are needed or used during the repairs, then it could throw the alignment out of spec. Technically speaking , the only specs that are adjustable on the new Defender are front and rear toe. JLR put no provisions in to adjust camber on the front or the rear which was very unfortunate to find out. (we are working on a cure for this). Front toe is adjusted using the front tie rods, so unless you replace a tie rod, steering rack or hit something relatively substantial like a larger pothole, technically no alignment is required. Most owners "know" when they need an alignment since they would feel the impact and possibly have a pulling or crooked steering wheel after the impact. Alignment will not just go out of spec by itself or over time. The rear also only requires an alignment if the rear forward control arm is replaced or there is an impact. You may not feel any pulling from a rear impact but u probably already hit whatever it was in the front 1st, so u get the idea. Tires will ultimately wear unevenly which will also give an indication of needing an alignment. The problem comes in when u hit something, not only can the toe get out of spec, but camber also, which you are then left replacing possible bent components, which usually is the subframe. As stated above when lifting or installing lift rods, you should get an alignment, because it will go out of spec. The tie rod and also the rear control arm actually do have the effect of becoming shorter because those arms now have a more aggressive angle on them. So during an alignment, the spec will be adjusted out to get back into proper spec. This is also a reason why the vehicle lowers or raises automatically (if equipped with air) when you get above a certain speed. It keeps you safely at the proper alignment since you align it at normal ride height. Most shops will "suggest" an alignment after installing new tires as a good practice to confirm proper alignment to prevent uneven tire wear. Unless you perform the alignment check you technically can not be sure your adjustable and non adjustable specs are within tollerences, so it makes sense to check and align at that point. Not required, but highly recommend.

 

You are both the best for these thoughtful & knowledgeable replies. Thank you @sarek + @Trekkie