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would just one hydro unit fail?
https://www.ausmini.com/forums/viewtopic.php?f=2&t=38061		 Page 1 of 2
Author:  Mort Subite [ Thu Nov 22, 2007 10:43 am ]
Post subject:  would just one hydro unit fail?
Hey gang

The 65Deluxe developed a problem last week, the front passenger wheel is now running with minimal clearance (not even one finger) between the tyre and the arch, (three fingers clearance on the other side no worries) and its also squeeking when moving, or being rocked side to side like the arm its resting on the rubber bump stop *squeek, squeek*.

I assume its the front hydrolastic unit that has failed in some way.
No loss of fluid.
From what I can see of the hose in the engine bay it looks fine.

.....and to confuse me further the rear on that side is still at usual height (in fact the rear sits a little too high in my opinion).

I was under the impression that if there was a fault in a unit the whole side would be effected as front and rear are connected/dependant on the internal preassure to retain ride height.

Any suggestions from the floor?

Assuming it is the unit that needs replacement - that would need to have the removal of the front subframe, engine, etc, right?

I cant see how to get to the unit as its behind metal panels.
Author:  miniron [ Thu Nov 22, 2007 10:56 am ]
Post subject: 
:?
Since its down only on one corner and no fluid leaks its most probably the LH front strut ball joint and plastic cup that has failed. Strut attached to hydro unit seats in a ball and socket joint on the upper arm. Happens often. Relatively easy to fix but you need access to a hydro pump.
I've been told it can be done by removing the upper suspension arm. It may come out easy but to put it back in????
Hydro bag is removed from the subframe through the area under the hydro unit where the upper arm pivots. There is a retaining bracket held in with 2? screws and the unit itself is held in place by a bayonet type mount. Turn unit a quarter turn to release. No need to remove engine subframe etc.

Hope this helps
RonR
Author:  simon k [ Thu Nov 22, 2007 12:49 pm ]
Post subject: 
squeak squeak sounds like the knuckle (strut ball & cup)

like miniron said, you'll need to depressurise the hydro, but don't need to take the bag out, just push the centre of it up and replace the knuckle - fairly quick job :)

the only thing that'd need to be undone is the wheel nuts and the little screw that holds the rebound pad in place - take the pad out so you can get the top arm down a little further
Author:  Mort Subite [ Thu Nov 22, 2007 1:39 pm ]
Post subject: 
Thansk for the leads

I had access to a BMC hydrolastic 'dalek' when I pumped the car up in March so that shouldnt be a problem.

So this failed 'knuckle' would make the wheel sit that 'low' in the arch?

Wouldnt the hydrolastic unit compensate (somewhat)?
Author:  simon k [ Thu Nov 22, 2007 2:49 pm ]
Post subject: 
Mort Subite wrote:
Wouldnt the hydrolastic unit compensate (somewhat)?


nah... all the weight is in the front, so when something goes, it'll always drop the front first
Author:  Matt68 [ Thu Nov 22, 2007 3:07 pm ]
Post subject: 
Mort Subite wrote:

So this failed 'knuckle' would make the wheel sit that 'low' in the arch?



yes it can.

Don't forget a small change in height here is worth a big change in ride height. I think it is around a 1mm change = 10mm of ride height on the front at the knuckle joint for a hydro car.

Cheers

M
Author:  Matt68 [ Thu Nov 22, 2007 3:22 pm ]
Post subject: 
Oh, And it could also be the aluminium trumpet piece between the bag and the knuckle, i had one of these go, the knuckle went out the side of it, and the car was on the bumpstop on that front corner.

Take the wheel off and have a look, that way you'll know if it's just a knuckle/ cup issue.

Beware of the top arm being worn too.

I found you need the radiator out to properly remove the front passenger side top arm. (for access).

Post us some pics.

M
Author:  drmini in aust [ Thu Nov 22, 2007 6:45 pm ]
Post subject: 
Matt68 wrote:
Oh, And it could also be the aluminium trumpet piece between the bag and the knuckle, i had one of these go, the knuckle went out the side of it, and the car was on the bumpstop on that front corner.

M

Trumpet? :shock: Dry cars have a trumpet and yes they rot when water gets in the top of rubber cone.
Hydros have a strut instead, it's a straight bit of bar/tube. These don't rot out.:wink:

re the suspension prob, my $$ is on a knuckle joint gone- when a bag goes there's fluid leakage, not squeaks. 8)
Author:  Morris 1100 [ Thu Nov 22, 2007 7:04 pm ]
Post subject: 
My Cooper S came with a broken piston in the bottom of the displacer. The piston is a cast aluminum cone that the knuckle joint fits into.
On my car the side had broken out of the piston allowing the knuckle joint to tip sideways.
You can remove the piston from the bottom of the displacer, it just clips into the rubber. :wink:
Author:  TK [ Thu Nov 22, 2007 7:11 pm ]
Post subject: 
I remember having an alloy trumpet on my hydro deluxe. Fitted between bag and knuckle joint. This does fail and the knuckle joint pokes out the side.
My bet anyway is a worn nylon cup in the knuckle joint.
Author:  Mort Subite [ Tue Nov 27, 2007 12:04 pm ]
Post subject: 
OK sounds like these are the things? Knuckle Joints?
I'm guessing I should replace all four (one each wheel)?

http://www.minisport.com.au/prod200.htm

Cant seem to find anything about the alloy piston/trumpet??
Author:  simon k [ Tue Nov 27, 2007 12:39 pm ]
Post subject: 
Mort Subite wrote:
OK sounds like these are the things? Knuckle Joints?
I'm guessing I should replace all four (one each wheel)?

http://www.minisport.com.au/prod200.htm

Cant seem to find anything about the alloy piston/trumpet??


yep, that's what you want... like you say, it might be a good idea to do them all... tho I'd get lazy and just replace the fronts

you won't be able to buy the alloy trumpet things new - but they'll be fine
Author:  Matt68 [ Tue Nov 27, 2007 1:20 pm ]
Post subject: 
TK wrote:
I remember having an alloy trumpet on my hydro deluxe. Fitted between bag and knuckle joint. This does fail and the knuckle joint pokes out the side.
My bet anyway is a worn nylon cup in the knuckle joint.


Yep, this is what I mean!

M
Author:  Morris 1100 [ Tue Nov 27, 2007 4:42 pm ]
Post subject: 
simon k wrote:
you won't be able to buy the alloy trumpet things new - but they'll be fine
Unless it is broken. They do break, I have one here in the bottom of a Cooper S bag.
Author:  simon k [ Wed Nov 28, 2007 10:13 am ]
Post subject: 
Morris 1100 wrote:
simon k wrote:
you won't be able to buy the alloy trumpet things new - but they'll be fine
Unless it is broken. They do break, I have one here in the bottom of a Cooper S bag.


ahh well.... if it's broken, I'm sure we'll be able to find a one for him
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