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Displacer failure
https://www.ausmini.com/forums/viewtopic.php?f=2&t=55006		 Page 1 of 2
Author:  66S [ Fri Jul 10, 2009 10:39 am ]
Post subject:  Displacer failure
Hi guys,
I finally have a set of S displacers to put my car back to Hydrolastic, but only three are good. I have a few rougher ones to choose the best from and I'm wondering if there is a common place they fail. If so, I need to pay particular attention to choosing a bag that is good in that area. Can anybody tell me where they commonly fail please?

Regards
Al
Author:  doogie [ Fri Jul 10, 2009 11:08 am ]
Post subject: 
Where the hose is connected to the bag, common failure point.

Doogie
Author:  66S [ Fri Jul 10, 2009 11:32 am ]
Post subject: 
Hi Doogie,
Thanks, do you know what happens there? Does the hose come off or does the crimped sleeve rust /fail or does the rubber come away from the steel and start leaking?

Regards
Al
Author:  doogie [ Fri Jul 10, 2009 11:35 am ]
Post subject: 
66S wrote:
Hi Doogie,
Thanks, do you know what happens there? Does the hose come off or does the crimped sleeve rust /fail or does the rubber come away from the steel and start leaking?

Regards
Al


Usually the unions rusts & eventually under pressure the hose just blows off.


Doogie
Author:  miniron [ Fri Jul 10, 2009 1:23 pm ]
Post subject: 
There is an Austin America site that has some info about repairing displacers. (Don't have the URL) I spoke to an bloke at an ENZED branch about repairing displacers and he said they can repair the hose connection point were it enters the displacer providing its not to badly corroded. From what I understand it seems that it is usually only the front ones that fail at the hose connection point as they are vertically mounted and water collects on top of the displacer and can't drain away. Rears are horizontally mounted and don't have this particular problem.

Hope this helps
RonR
Author:  66S [ Fri Jul 10, 2009 1:35 pm ]
Post subject: 
Hi Ron,
I too have spoken with Enzed re replacing the hoses if necessary. They reomove the hose and hose stem, drill the hole and tap it to take a hose fitting. I have a couple of displacers that are OK in that area but the diaphragm at the other end is looking cracked and a little second hand. Nobody so far has mentioned the diaphragm bursting, so maybe my concerns are a little ill founded.

Thanks and regards
Al.
Author:  4myego [ Fri Jul 10, 2009 4:05 pm ]
Post subject: 
As Doogie said, The main area to watch is around the swagged hose connection of the top of the bag. My one burst because of extreme corrosion. I found that normally the metal stem inside the hose to bag is OK. So you can get out of trouble by running a 1/8 BSP die nut down and have a hydraulic hose made up to suit.

It is critical that you run the die nut down the stem perfectly square. If it runs off slightly you will go through the stem wall (found that one out the hard way :oops: )

Just look for the best bag which has no rust / corrosion around this area. Lower rubber boot seals are easy to get.
Author:  Morris 1100 [ Fri Jul 10, 2009 6:27 pm ]
Post subject: 
I have had three blow the top out of the bags over the years. Two on my first Morris 1100 and one on a Mini. I have also had one bag start weeping at the hose fitting.
The two 1100 ones that blew split where the rubber spring joins to the steel bit that the hose fitting is mounted in. It was just like when an engine mount tears off the steel.
I can't remember what failed on the Mini one. (CRAFT disease) I think it was the top of the bag where the rubber spring joined the outer case of the displacer.
Author:  66S [ Sat Jul 11, 2009 6:35 am ]
Post subject: 
4myego wrote:
. Lower rubber boot seals are easy to get.


I have removed the boots and the diecast centre piece, it is the diaphragm behind the diecast centre piece that has me a little concerned. Thanks for youyr comments.

Al
Author:  miniDave [ Sat Jul 11, 2009 8:08 am ]
Post subject: 
2 S's & a clubman wrote:
66S wrote:
Hi Doogie,
Thanks, do you know what happens there? Does the hose come off or does the crimped sleeve rust /fail or does the rubber come away from the steel and start leaking?

Regards
Al


Usually the unions rusts & eventually under pressure the hose just blows off.


Doogie


I remembered this photo from last year. You can see that water has rusted the collar and eventually breaks down which leaves the hose to come off under pressure.
Image
I repaced the front displacers with ones from the rear that were in much better condition.

Regards
Author:  66S [ Mon Jul 13, 2009 9:57 am ]
Post subject: 
Thanks for the photo Dave. Two of the bags I have have some corrosion damage there but aren't too bad. As I said earlier, there is some cracking/perishing in the diaphragm at the other end and the rubber has come away from the steel around the hose end. I've urethaned it back together there and I'll pressure test them before I go too far.

Regards,
Al
Author:  Mick [ Mon Jul 13, 2009 10:20 am ]
Post subject: 
Water gathers on top of the bags, and has little air movement through to dry it out. This would easily cause the corrosion to occur from the outside in on the fitting. I think there's a drain hole drilled around the rim, I might be wrong...so check if one is there to be cleaned out..

I reckon there's not much you can do to repair the previous 40 years of neglect, but before I put mine back in the car I painted the fitting photographed above with a thick coat of paint, and them fish oiled it heavily. I was able to use my glass bead blaster to clean it all up prior to this (It also makes the rubber look fantastic once again if you hit it with glass bead)
Author:  drmini in aust [ Mon Jul 13, 2009 7:27 pm ]
Post subject: 
There is supposed to be a rubber condom doohickey (hydrolastic hose protector 21A1515) on the hose and a metal retainer 21A1487 above it on the crossmember. Kept the H2O out originally.

see p204/205 in the MiniKing cattledog.
Author:  gafmo [ Mon Jul 13, 2009 8:40 pm ]
Post subject: 
drmini in aust wrote:
There is supposed to be a rubber condom doohickey (hydrolastic hose protector 21A1515) on the hose and a metal retainer 21A1487 above it on the crossmember. Kept the H2O out originally.

see p204/205 in the MiniKing cattledog.


I'v never seen one..I guess they rusted away long ago :shock:
Author:  66S [ Tue Jul 14, 2009 6:03 am ]
Post subject: 
drmini in aust wrote:
There is supposed to be a rubber condom doohickey (hydrolastic hose protector 21A1515) on the hose and a metal retainer 21A1487 above it on the crossmember. Kept the H2O out originally.see p204/205 in the MiniKing cattledog.


I haven't got catalogue but it must be an Aussie part. English/NZ cars have a white plastic sleeve that guides the hose through the bulkhead at the front and subframe at the rear. At the best, the front ones stop water getting into the car through the master cylinder/pedal opening. They do nothing much to stop water getting to the top of the displacer.

Even if the hose hole was sealed, road wash could easily get in, so I figure it is probably best to leave them open so that water that does get in can evaporate.

Regards
Al
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