Grove Brake System Fluid

[skippydiesel]

I am in need of the brains trust advice;

 

My new  RAA class, aircraft comes fitted with Grove brakes. Grove web page advises (after much superfluous information) to use MIL PRF-087257 hydraulic fluid in their systems. My old aircraft used DOT 4 automotive - easy find and relatively cheap. 

 

What would your recommendation/suggestions be??

[Thruster88]

Use the recommended hydraulic oil. Your local friendly LAME will sell you a can of aeroshell 41 fluid. Using automotive brake fluid will damage all the rubber components.  

[facthunter]

That one is a mineral oil and only suitable for synthetic rubber type hydraulic fittings. Nev 

[facthunter]

There's a less flammable option on their website. If you have a Lancair or such. It's a very comprehensive website. Nev

[skippydiesel]

2 hours ago, Thruster88 said:

Use the recommended hydraulic oil. Your local friendly LAME will sell you a can of aeroshell 41 fluid. Using automotive brake fluid will damage all the rubber components.  

Maate! I fly 19 so that I dont always have to pay the ridiculous aviation product prices. The Grove system I am filling, uses a few cc's not litres  a can of Aeroshell will last me several lifetimes and its not compatible with my ground vehicles.

[Thruster88]

2 minutes ago, skippydiesel said:

Maate! I fly 19 so that I dont always have to pay the ridiculous aviation product prices. The Grove system I am filling, uses a few cc's not litres  a can of Aeroshell will last me several lifetimes and its not compatible with my ground vehicles.

If you were closer I would give you some. Not sure what other option you have, use the correct product or take a risk with somthing like automatic transmission fluid. May not be cheap in the long run. 

[facthunter]

You could use it for general machinery oil. Ordinary auto hydraulic fluid is hygroscopic and  ruins paint. Another fluid is silicone but that has a more limited application. You should bleed your system every few years at least. I would recommend from the calliper back to each master cylinder. (uphill) Nev

 

[skippydiesel]

 

FYI;

 

Aero Shell 41 is approved to MIL-PRF-5606H ( obtainable from Sky Fuel for $19/quart?) How does this compare with MIL PRF-087257 ???

 

Aero Shell 31  is approve is to MIL PRF-087257 but does not seem (at this time) to be available in smaller quantities.

 

When I Google MIL PRF-087257, I get products like FEBI Hydraulic Fluid - 24704 

[Thruster88]

The MIL PRF 5606 is one of the approved standards for the grove system so aeroshell 41 is ok. It is what we use at work for cessna piper beech brakes.

[skippydiesel]

12 minutes ago, Thruster88 said:

The MIL PRF 5606 is one of the approved standards for the grove system so aeroshell 41 is ok. It is what we use at work for cessna piper beech brakes.

Sounds promising - at some stage I will be able to fly into Cowra for a visit- but without brakes this might not be such a good idea🤣.

 

Do you happen to know what the the differences are between Aero Shell 41 & 31 (in simple language)?

 

Will contact Sky Fuel next week

[Thruster88]

3 minutes ago, skippydiesel said:

Sounds promising - at some stage I will be able to fly into Cowra for a visit- but without brakes this might not be such a good idea🤣.

 

Do you happen to know what the the differences are between Aero Shell 41 & 31 (in simple language)?

 

Will contact Sky Fuel next week

Aeroshell 41 is mineral oil. 31 is $ynthetic😂

[onetrack]

Aeroshell 31 is the specified compatible synthetic hydraulic fluid that meets MIL PRF-087257 specs. But it's certainly not cheap. The PRF-087257 specs sounds like overkill to me, for an RA aircraft. Like -40C to 205C temperature range? And super-finely filtered? Yes, if you were putting it in military aerospace vehicles, but I don't see where it's needed in an RA-aircraft.

Have you thought about silicone brake fluid? It's not hygroscopic, doesn't react with any metal or brake component material, such as special seals, nor any natural rubber, and it is very stable. Plus, silicone brake fluid does not damage paintwork, if spilled on it. Current spec DOT 5 brake fluid is a silicone brake fluid.

 

https://www.flightstore.com.au/aeroshell-fluid-31-3.7ltr

 

Edited December 11, 2021 by onetrack

[facthunter]

Silicone based doesn't have the "oiliness" of the others and there may more wear of the master cylinders where there's side load from the angularity of the actuator rods.. Just stick to the basic oil (41) which is available anywhere and the manufacturer recommends for normal use .Nev

[skippydiesel]

3 hours ago, facthunter said:

Silicone based doesn't have the "oiliness" of the others and there may more wear of the master cylinders where there's side load from the angularity of the actuator rods.. Just stick to the basic oil (41) which is available anywhere and the manufacturer recommends for normal use .Nev

So you would not use AeroShell 31 (silicon)  that meets the Grove MIL PRF-087257 standard but woud use the Shell41 (mineral) that may also meet the Grove standard but is not top of their preferred brake fluid list?

[facthunter]

AS I said do you fly a Lancair?  IF not you don't need a high performance oil to be less flammable. I know someone whose Lancair burnt to the ground after a high speed rejected take off  and brake fire. You are not in that category.. Nev

[skippydiesel]

Fair enough.

[Flightrite]

Shell 41, the STD in the industry been using it for ages.

[skippydiesel]

My thanks to all the well informed respondents - AeroShell 41 would seem to be the most cost effective & available solution to my original question.

 

Cant understand why component suppliers/manufacturers to RAA class/type  aircraft, can not supply systems that are compatible with more readily available/cheaper automotive products. In this example (Grove brake system) it would just require the option (at time of purchase) of fitting seals that are compatible with automotive brake fluids - how hard could this be ???. 

[facthunter]

The general, the most used auto type is a pain. It absorbs water once the can is opened  and ruins paint. You are lucky your system doesn't use it. It's mainly required because of high disc brake temperatures and should be bled frequently to avoid absorbed water ruining the brake performance. You need to recondition the Calipers also as rust is common with that fluid. Pistons have to be chromed. It can corrode aluminium parts also.. Nev

[skippydiesel]

9 hours ago, facthunter said:

The general, the most used auto type is a pain. It absorbs water once the can is opened  and ruins paint. You are lucky your system doesn't use it. It's mainly required because of high disc brake temperatures and should be bled frequently to avoid absorbed water ruining the brake performance. You need to recondition the Calipers also as rust is common with that fluid. Pistons have to be chromed. It can corrode aluminium parts also.. Nev

Confused - are you laying all those negative attributes on Dot3/4 or AeroShell 41 

 

If Dot3/4  - I have never heard so much BS.

 

Yes Dot 3/4 is hydroscopic, that why I  (& you should) replace brake fluid every 18-24 months & dont  have any problems.

Never had rust in any of my vehicles brake systems .

What fool leaves a container of brake fluid unsealed - tighten the lid and no atmospheric moisture can enter.

The person who spills Dot3/4 over paint & doesn't immediately clean it up,  deserves to have an issue. 

Your alarmist observations can only be for vehicles not appropriately maintained and that is no  justification bagging a perfectly functional hydraulic fluid, that has been around doing sterling service, for at least the 50 years (befor disk brakes became common) I have been maintaining my own vehicles.

[facthunter]

Bit of an over reaction isn't it?. I'll stand by everything I've said. 1/2 used brake fluid containers should be discarded.  You don't keep them long once opened. I'm trying to answer  questions YOU raise. . Nev

[onetrack]

Leaks from brake systems are not uncommon, and when the fluid leaks, you get damaged paint.

Not everyone is as anal about brake fluid changes as Skippy, otherwise the brake repair places, and the stainless and chromed piston retailers would be out of business in quick-smart time, if that was the case.

In my restoration and repair work, corrosion and brake system components are constant companions.

[facthunter]

Ant skid components and the split system master cylinder s are a problem. When you take the cost of your time into it REPLACE becomes the best option. On older cast iron stuff, l I used to use Hydraulic and General Sleeving. to do stainless sleeve inserts...Combined rear discs with hand brake operating on them are interesting.  Nev

[skippydiesel]

5 hours ago, onetrack said:

Leaks from brake systems are not uncommon, and when the fluid leaks, you get damaged paint.

Not everyone is as anal about brake fluid changes as Skippy, otherwise the brake repair places, and the stainless and chromed piston retailers would be out of business in quick-smart time, if that was the case.

In my restoration and repair work, corrosion and brake system components are constant companions.

Is great that you are able to benefit from the negligence of others and yes I confess to being "anal" however I would also point out that so many people are focused on making their vehicle/aircraft/whatever go better/faster and somehow forget that at some stage it might just be a tad important that you can reliably stop the darn thing.

 

Brake fluid changing/bleeding is such a quick, cheap and easy thing to do,  compared with the cost of a brake component repair due to corrosion and  a lost life/injury due to brake failure.

[skippydiesel]

6 hours ago, facthunter said:

Bit of an over reaction isn't it?. I'll stand by everything I've said. 1/2 used brake fluid containers should be discarded.  You don't keep them long once opened. I'm trying to answer  questions YOU raise. . Nev

Dear Nev, I did not raise issues regarding DOT 3/4 break fluids -  I sought advise on locally available MIL PRF-087257 hydraulic fluid meeting MIL PRF-087257. That advise has been give - AeroShell 41 would seem to be the right product-  readily  available & cost effective. True I winged about the inflexibility of aircraft component suppliers not having an option to supply a product using off the shelf (automotive) service items.