Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Slow front shocks
My suspension seems fine other than when raising the front is very slow. The rear pops up but the front can take what seems ages by comparison. I don't think it's the compressor or the rear's wouldn't rise so quick. the cylinder seems also OK because if I cycle up and down the rears always go quick and the fronts slow.
It's also (I think) not a strut as they work together well enough, just slowly
Do blockages happen in the valves or pipe runs? if so what's the cure?
I'm just getting started at this having bought a 12 D4 a couple of weeks ago.
Thanks for any advice given.
7th Jul 2018 10:32 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
The computer raises the rear first.
If the compressor/tank runs out if air it always appears that the front is slow
When it's not the fronts fault.
7th Jul 2018 10:40 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Thanks Pete, that makes sense then. How much is the tank supposed to hold? more than one cycle I take it...
My slow shocks happen at any time, I'd of thought the cylinder would be well charged after a run so would than mean my compressor is struggling to produce enough psi?
7th Jul 2018 10:44 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
Tank should allow lots of changes betweeen access and normal.
Compressor sounds most likely
8th Jul 2018 7:32 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hi
Don’t know if this chart may be of use
Click image to enlarge
8th Jul 2018 7:34 am
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Pete K wrote:
Tank should allow lots of changes betweeen access and normal.
Compressor sounds most likely
After a bit more experimenting I've become more convinced that this is not a pressure problem as the car will happily cycle through the levels always pumping up the rear fast and always fronts (up or down) very slow but straight back up again no problem. I've also had it go into extended mode as the sensors are sensing the suspension is not lowering fast enough and thinking the car is grounded I guess. When it does, extended and extra extended happen at the same rate but if I'm thinking right must take a fair bit more pressure than the std level so there must have been plenty of pressure for the front shocks at normal height, right?
Has anyone had sticky shocks or a partially blocked front valve? and what symptoms did it cause?
15th Jul 2018 7:53 am
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
gstuart wrote:
Hi
Don’t know if this chart may be of use
Click image to enlarge
Thanks, thats quite a pressure drop for the 4, did they go over to a bigger shock?
15th Jul 2018 8:00 am
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20731
I’ve seen D4’s with a much higher gallery pressure than 1300kpa My D3 Build Thread
Member Since: 02 Dec 2016
Location: blackpool
Posts: 406
Just changed my front shocks, dead easy to do, just rear nut on top a bit fiddly, not that expensive either, £340 delivered from Island 4x4 OEM.
Rears next week.
15th Jul 2018 8:41 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
I think your thinking along the right lines baz.
Check exhaust if slow to lower.
Maybe pipe to front is kinked?
15th Jul 2018 10:05 am
omg!
Member Since: 01 Jun 2011
Location: Fife
Posts: 569
My car has always behaved like this.
It lifted the rears first before and after the front airbags were replaced and it did it before and after the compressor was replaced.
As far as I can see, for may car, that's normal behaviour.
15th Jul 2018 10:33 am
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
The lifting order is normal, they lift the rear 1st so as not to send the headlight beam up in the air (well thought out really) It's just the fronts are very sloooow. on mine!
15th Jul 2018 5:31 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
Very Bizarre this morning lowering from any level triggering extended mode and the car rising quicker than ever before, it did about 3 cycles like this before going slow on the fronts again.
So, could be height sensors but they look ok on the 4x4 app.
Could be a trapped tube somewhere but then why sometimes fast and sometimes slow?
Could be the compressor (weak on psi) but it's just demonstrated good psi for several cycles.
Maybe the dryer? does the released air pass back through it, if it's getting blocked that could be erratic.
could be the shocks sticking? I think I might load the D4 up with people & stuff to see if it drops any quicker and avoids triggering the extended mode.
All this happens while still (engine running). As soon as I get the D4 moving the suspension seems to drop without fuss.Disco 4 2012
24th Jul 2018 2:45 pm
grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6266
I have similar behaviour including heigh going to offroad if car was sitting in access for a while for some reason.
24th Jul 2018 2:51 pm
Bazza.
Member Since: 06 Jul 2018
Location: Essex
Posts: 332
It makes it very difficult to pin point the fault.
I've seen one report of a guy who changed just about everything without curing it. air shocks, pump etc.
If it was the dryer it would be common to front and back.
I keep coming back to sticky shocks or front valve/pipe system.Disco 4 2012
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