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Hydrolastic Suspension Replacment
https://www.ausmini.com/forums/viewtopic.php?f=2&t=82777		 Page 1 of 2
Author:  Morri68 [ Tue Sep 17, 2013 5:25 pm ]
Post subject:  Hydrolastic Suspension Replacment
Hi, I was wondering if you can still buy new hydro bags and the flexible hoses if not were do I get replacement bags and hoses from?
Author:  Mick [ Tue Sep 17, 2013 5:46 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
No, they haven't been available for many years, but are available as second hand units easily enough with rear units usually being in slightly better condition than the fronts. The hoses are integral to the bags, and are not available separately.

Saying that, the hydro hags are repairable if the hose has developed a leak at the point where they enter the hydro bag itself.
Author:  Morri68 [ Tue Sep 17, 2013 5:57 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
Can they be made at all?
Author:  mini_mad_matt [ Tue Sep 17, 2013 6:07 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
There are some places that can make a new hose for them and maybe someone near you can recommend one.

There are 2 places local to my work which used to do them, but 1 now refuse to. I'd say because the person that used to do it and knew what they were doing had left and the new workers weren't interested.


I think dr.mini might also have made a thread about putting new hoses on
Author:  Morri68 [ Tue Sep 17, 2013 6:23 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
So would these secondhand ones be perished or would they be still good to put on and do they put the body tar on the bags?
Author:  Kennomini [ Tue Sep 17, 2013 6:43 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
Most 2nd hand ones that are sold are in useable condition, some people (Dr mini has a jig from memory) can pressure test them before installation.
Being 2nd hand, 40 year old parts they can't be guaranteed but you have to take it on good faith that the seller believes they are in useable order and they can be tested like I mentioned but the replacement bags may only last 1 week after installation or they may last another 40 years.
Author:  drmini in aust [ Tue Sep 17, 2013 7:21 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
The hose failure is usually because with old age it rots inside the metal crimp where it fits on the barb.
Hydro bags have not been made in Oz since Dunlop closed their factory (now Birkenhead Point shopping centre).

It is possible to fit new hoses, here's one I prepared earlier by cutting the barb off, tapping a 1/8 BSP thread in there then fitting a 1/8 x 3/8 BSP brass nipple. I then had Pirtek crimp some MPH-06 hose to a 3/8 BSP flare fitting. This hose is rated 500psi and is similar construction & flexibility as the original hose.
Before anybody asks, NO I have had no joy finding any Dunlop Diamond pattern hose as used on these bags 40+ years ago.
Note- the flare fitting at the outer end of a standard hose is 5/8-18 UNF thread. I have been unable to source new ones here, but you could remove and re-use your old ones.
The end fitting on my prototype hose shown is 3/8 BSP, I then made an adaptor to fit it to the rear subframe hydro fitting for testing.

http://www.flickr.com/photos/31275265@N05/8798837447/
http://www.flickr.com/photos/31275265@N05/8798852405/

Test rig is a dead S rear subby with a bit of SHS tube welded to it. The pump is a Mini clutch MC mounted on a Fiat pedal box.
http://www.flickr.com/photos/31275265@N05/9711727885/
http://www.flickr.com/photos/31275265@N05/9714960808/

There are other methods of fitting a new hose, however this method allows you to make a hose complete with screwed fitting both ends. easy to fit...
Author:  69k1100 [ Tue Sep 17, 2013 8:51 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
Generally the construction of the bag means they don't usually fail internally. So you're ok there but the outer steel shell can rust which can be a problem.

http://m.flickr.com/#/photos/moultonbuzz/3918522271/
Author:  Morri68 [ Tue Sep 17, 2013 10:41 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
Can you rebuilt the bag internally if it fails
Author:  drmini in aust [ Wed Sep 18, 2013 8:28 am ]
Post subject:  Re: Hydrolastic Suspension Replacment
I would say no, as I cannot see how you would get it apart without destroying it.
However if somebody has done it, I'm all ears... :D

The internal bits that seem to deteriorate with age are the damping valves. However this can be overcome by robbing a pair of front shock upper brackets from a dead Mini, then adding a new pair of shocks to the front only. [edit] See my fitting shockies thread in the how-to forum. viewtopic.php?f=25&t=12180

IMO for road use you do not need or want these shocks too hard. A set of KYBs or standard replacement ones is fine. I have had Pedders reds on mine for 10+ years and they are still good.
Author:  TheMiniMan [ Wed Sep 18, 2013 9:10 am ]
Post subject:  Re: Hydrolastic Suspension Replacment
I have a few 2nd hand bags here if anyone needs them
Matt
Bne
0407 135 656
Author:  Morri68 [ Wed Sep 18, 2013 4:12 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
is it normal for the front to sit a fair bit lower than the rear with the hydro bags, it has been sitting for quite some time is this a sign of internal failure or is it a common thing to happen.?
Author:  69k1100 [ Wed Sep 18, 2013 6:59 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
Common from what I read. There are a set of springs at the back to help pull up the front, but they're usually knackered after 40 years.
Author:  drmini in aust [ Wed Sep 18, 2013 7:09 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
You can also fit a spacer washer between the front knuckle joint and the strut to raise the front. There was a thread about this here recently.

Regarding the rear springs there were 2 types, the later ones (orange) were stronger. There are still spring makers here in Oz who could make some to a sample (I suggest making them a little shorter so they pull down more).
Author:  Morri68 [ Wed Sep 18, 2013 7:34 pm ]
Post subject:  Re: Hydrolastic Suspension Replacment
So the height difference is a common issue
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