Hydrolastic Tool

[CALIMKIIIS]

I found this hydrolastic evacuation/pressurization tool on eBay U.K., won the auction and received it this week. Said to be a 'factory' service tool and used only once and from what I gather it is a rather rare item. It arrived in what seems to be in excellent condition. At the same time I had shipped a liter of genuine Rover Hydrolastic fluid from Mini Sport. The unit came without instructions so I now need to find out how to properly use it. I've had my 'grease gun' type of hand pump for many years to pump the car up every couple of years. Now I've had to have the L/H rear displacer refurbished by Hydragas and Hydrolastic Services Ltd. as the displacer hose failed. Of course the reason to get this tool is that I'll need to evacuate the system once everything is re-assembled and the car back on the ground before I re-pressurize. It's obvious that the red switch determines which mode the tool is in for each function. I don't want to overthink things or the reverse but would welcome any input from anyone familiar with this device. I would think that one liter of fluid would be sufficient to operate either function. It occurs to me that once I were to evacuate the system I would close the valve and remove it from the Schrader valve fitting. The next question would be that then wouldn't the vacuum created open the Schrader valve and suck air back in? If not, great as I would then switch the unit to pressure mode, fill the line with fluid, connect it to the valve fitting and pressurize the system as normal. Here's photos of the tool:

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[111Robin]

This tool doesn't have a vacuum capability, it's for pressurising only (I can only see a pressure gauge for one thing). This isn't really an issue as most people don't bother to evacuate before pumping up the system, just pump it up and then vent back to the tank two or three times before final pressurising. It doesn't look like there is a bleed valve before the Schrader low loss valve so I would first loosely screw the Schrader valve onto the car (with the low loss T-bar screwed out fully), close the pump valve and pump fluid through until it squirts out of the low loss valve. Then fully make up the low loss valve to the car. I'm assuming there is no pressure in the system as you are filling it so you can just screw in the low loss T-handle to unseat the Schrader valve then (pump valve still closed) fill up the system fully until the maximum height/pressure is achieved. Rock the car from side to side a few times then slowly crack open the pump valve to allow the fluid to vent back to the tank. Close the pump valve and repeat this another couple of times to purge as much of the air out as possible. Pump up to the final desired height/pressure. Before you open the pump valve,, back out the low loss valve. You can then open the pump valve to bleed off pressure from the tool line.

If you are connecting the tool to the system already pressurised, before you screw in the low loss valve pump up the tool to approx. 200psi otherwise the suspension will drop when you open the Schrader valve. You have to approximately equalise the tool/car pressures before opening the Schrader.

I think this is correct, if not there are plenty on here with hydrolastic knowledge who will chip in. To be honest I don't know if this is a factory tool, perhaps it is the type that they used on the MGF latterly, it's certainly not of the vintage that would have been used on Minis but is perfectly fine for doing so.

[CALIMKIIIS]

Thanks for your input! About the gauge though, this one has dual reading, for vacuum (bar) and pressure PSI, leading me to think the tool is designed to evacuate as well as pressurize?

P1012996.JPG

[111Robin]

Afraid not, it's only measuring pressure in metric (bar) and imperial (psi) units. To evacuate the system requires only around 810 millibar (0.8bar)(or 24 inches of mercury in imperial units). Your pump is only for pressurising.
The two position valve is simply either open (vent back to tank) or closed ( pressurise). It isn't vacuum/pressure.
The original factory pumps incorporate two seperate pumps and gauges for vacuum and pressure, they can't be incorporated into a single pump/gauge unit.

[CALIMKIIIS]

Thanks again for your response! The seller on eBay said he used the unit to 'drain' and refill his mini but didn't use the word 'evacuate'. Unfortunately I paid stupid money for this thing. Well I suppose I'll now need to replace the fitting on the end of the hose with the type I've seen that has has a vacuum nipple off to the side and then buy a vacuum hand pump to evacuate the air from the system. The next question might be that having evacuated the system under vacuum, would I then open the valve with the pump and line filled with fluid which may then reverse the flow of fluid into the system and stabilizing it to neutral pressure before re-pressurizing? Trying to be as clear as possible, sorry..

[CALIMKIIIS]

I did notice you mentioned it may not be necessary to evacuate the system, instead refill and drain back several times until no air seems present. That would be nice indeed if I didn't have to buy an extra fitting and vacuum hand pump. My concern is that I'll be re-fitting a refurbished displacer which will be void of fluid therefore much air to remove. I read somewhere that it's advisable to fill or partially fill the displacer before installing it, presumably to have less air to evacuate before pressurising the system?

[111Robin]

You don't need to buy anything else, just follow the procedure I gave. Yes you can just pour hydro fluid into the displacer before fitting, it will reduce the time to fill. It sounds to me as if you are not sure about this so please take great care and follow the procedure safely, wear safety glasses at all times. A few hundred psi will be in the system so you must be very careful. You could always speak to Ian or Dawn from whom you had the displacer repaired, they will keep you on the right track. They also sell new tools similar to the one you just bought, I'm surprised you never discussed this with them before buying this one, probably cheaper to buy one from them.

[GraemeC]

This looks essentially the same tool, so maybe MiniSpares can supply a copy of the instructions
http://www.minispares.com/product/class ... vwQAvD_BwE

[mk1]

That's the same as the one Rich & I have had for years.

As has already been said, it won't evacuate, it only pumps up. You can use it for "draining the system. Connect it up, turn the red knob & the fluid drains out. Turn the knob the other way & you can pump the system up.

If you don't have a vacuum facility just pump & drain a few times, this works nearly as well as vacuuming the fluid out.

These are the best value units currently available.

https://www.ebay.co.uk/itm/HIGH-CAPACIT ... SwY3tbR4ap

[CALIMKIIIS]

Thanks all! Still glad I bought the tool I now have, paid 255 GBP + 60 shipping, still less then a new unit. As said, I've used a hand pump to pressurize the system for many years as needed to raise the suspension an inch or so every couple of years, (to 292 PSI as recommended) so I'm familiar with that procedure and attendant safety precautions. The nice thing about the pump I recently acquired is that I can drain fluid out whereas not so with the 'grease gun' style hand pump. I considered consulting Ian and Dawn at H&H Ltd, about pumps etc. but didn't want to burden them with having to explain things until I had confidence in having the right questions. Also I'd already bought the pump around the same time I sent them my displacer. As of yesterday I did e-mail Dawn about filling the displacer before installation but haven't heard back yet. Glad that question was addressed here, thanks! There is a similar unit on eBay right now and the seller did show pages from it's instruction manual which I nicked for my file. In the past I've usually pumped up the system to around 300PSi, rocked the car, let things settle, drive it around a bit, let it settle some more then later bleed off a little fluid to lower the car about 1/2 to 1 inch. Some say use the '4 finger' measurement from tyre to wheel arch, I tend to go for 3 fingers at the front, just a personal preference. As part of the project I did get a new inner subframe bump stop, new knuckle, seat and gaiter, new felt washers for the helper spring mount, proper British grease and will add a pair of the 'Swedish' bump stops I've had for years..

[111Robin]

Sounds like you're on the case now. The only other thing to add is that once you first pressurised the system, it's a pity to then vent back the old dirty fluid into the tank filled with clean fluid. Probably best to empty the tank after pressurising the system, vent the old fluid back to the tank, dispose of the dirty fluid then refill with clean fluid and repeat the process.

[CALIMKIIIS]

Excellent advice as usual! Good point about the fluid contamination aspect, something I will do. Even though the fluid that came out of the car was still a lovely green colour, what came out of the removed displacer was a muddy brown, so note taken. Given that I can't get hydro fluid here, I have to import it from Mini Sport in this case, costing me the equivalent of 50 GBP per liter with shipping, so I don't need to pollute that any more than necessary! I will be following everyone's advice to pump and refill several times as recommended...

[winabbey]

Given that I can't get hydro fluid here, I have to import it from Mini Sport in this case, costing me the equivalent of 50 GBP per liter with shipping, so I don't need to pollute that any more than necessary!

Many hydro suspended Mini owners here in Oz make their own fluid rather than buying what is effectively the same stuff from a Mini parts supplier in a fancy bottle. It's basically common anti-freeze in a 50/50 mix with water.

Here's the recipe BMC Australia documented in its training school for the Morris 1100 (see towards the end).

TP707 Hydro Suspension p1.jpg

TP707 Hydro Suspension p2.jpg

[winabbey]

BMC Australia did play with the recipe in the mid-60's to eliminate apparent squeaking.

C 63_65 p1.jpg

C 63_65 p2.jpg

C 63_65 p3.jpg

[CALIMKIIIS]

Excellent information! Having recently learned so much about the fine points of hydrolastic suspension, tools and techniques, many posts on the subject to be found on here, such a great resource I must say! I did look at the ingredients on the jug of the MG Rover fluid and it only states 50% ethylene glycol. Basically just engine coolant and water with possibly some unspecified lubricant or corrosion inhibitors? Hopefully they've added as with the OZ formula, something to bitter the taste as without it is said to have a sweet flavour that would be attractive to cats and dogs which would be fatal. I recently read of a home recipe that was basically 50% ethylene glycol, 50% distilled (demineralized) water but they added something like a spoonful of silicone brake fluid as a rubber-friendly lubricant. As that BMC Bulletin states, one could add an additional amount of lubricant to increase the viscosity and therefore stiffen the ride but I doubt many would be willing to experiment much, at least not on their own car!