Seals from master brake cylinders and clutch cylinders dissolving!!!

[Dieter H. Marschall]

Hello everybody,

After I had bought some aftermarket master brake cylinders and clutch cylinders I did what I thought might be best: I applied ATE brake cylinder paste (see here: http://www.ate-info.de/de/products/d...-paste-180-ml/), as "red rubber grease" is not available in Germany.

When I checked those items recently I saw to my great surprise that some of the rubber seals had simply dissolved into a black, pasty substance!

What did I do wrong? Buy the wrong seals or the wrong grease?

ATE confirms that their product is designed especially for brake and clutch parts - including the rubber seals...?

Kind regards form a puzzled
Dieter.

[martin]

Hi Deiter, were the seals you fitted, new old stock, or were they new ? without any names, did you buy them in UK ? Martin.

[dasadrew]

Dieter,

I have used that Ate blue paste as long as I can remember - from before the time when Pontius got his Pilate's license. Never any problems. I don't believe the grease is the culprit.

[dasadrew]

Dieter, just had some more thoughts on this, but your post is not quite clear. You said you bought some new brake cylinders, then later you ask if you bought the wrong seals. Did you replace the seals on new aftermarket cylinders? Secondly you say you checked them? So are these cylinders in use on your car or are you storing them?

I can't find it anymore, but I can remember some shreds of information that, if you mix brake fluids (especially silicone and traditional) this can lead to seal degradation.

In any case, don't the seals deteriorate normally a bit anyway? I thought that was one of the reasons that old brake fluid is black??

[Dieter H. Marschall]

Hi Deiter, were the seals you fitted, new old stock, or were they new ? without any names, did you buy them in UK ? Martin.

Hello Martin,

Those seals came with the cylinders and were sold as "new" by a UK company. The corpus of the cylinders says "Girling .70".

Best wishes,
Dieter.

[Dieter H. Marschall]

Dieter, just had some more thoughts on this, but your post is not quite clear. You said you bought some new brake cylinders, then later you ask if you bought the wrong seals. Did you replace the seals on new aftermarket cylinders? Secondly you say you checked them? So are these cylinders in use on your car or are you storing them?

I can't find it anymore, but I can remember some shreds of information that, if you mix brake fluids (especially silicone and traditional) this can lead to seal degradation.

In any case, don't the seals deteriorate normally a bit anyway? I thought that was one of the reasons that old brake fluid is black??

Hello Drew,

As I wrote to Martin already: I had bought those items as complete, "new" cylinders, which I took apart, greased them with "ATE paste" and then stored them in my rack. So they never were in contact with any brake fluid.

In one case the main seal simply dissolved and in three cases the rear seal did so. Other seals were not affected...

Best wishes,
Dieter.

[martin]

Hi Dieter, can you PM me who you got them from ? Martin.

[Dieter H. Marschall]

Hi Dieter, can you PM me who you got them from ? Martin.

Hello Martin,

I must be crazy as over the years six different TR6 cylinders "accumulated" in my workshop. They are all marked "Girling .70" or "Girling 3/4", but with varying displays of inscriptions. I am afraid I have no (more) clue which one came from which seller...

Kind regards,
Dieter.

[martin]

The thing about rubber components is that they decay with age, even if kept boxed in the dark. I'd replace them with new (cheap) and just assemble with brake fluid. Do let us know how you get on. Regards, Martin.

[Dieter H. Marschall]

The thing about rubber components is that they decay with age, even if kept boxed in the dark. I'd replace them with new (cheap) and just assemble with brake fluid. Do let us know how you get on. Regards, Martin.

Hello Martin,

I reckon this is a "no win situation". If you use brake fluid, this tends to bind water thus leading to rust. If you use a paste, you end up with your seals dissolving.

Although I used a special brake cylinder paste from ATE (http://www.ate-info.de/de/products/d...-paste-180-ml/) those seals became jelly...

I wonder whether "red rubber grease" would have done a better job. What do you think?

Best wishes,
Dieter.

[martin]

Hi Dieter, I have no knowledge of rubber grease at all. If your storing them, keep them dry, if fitting, use brake fluid. Martin.

[73stagman]

I will butt in here. The most likely culprit is time. All "rubbers" degrade over time and "new old stock" seals and cylinders will have old seals in them even if they have never been used with grease brake fluid or oils. Even if the seals have been stored in dry and dark conditions the likely hood is that the rubber component will have started to degrade... any mineral component of any lubricant will destroy them.

The "win" way to go forward is to use new good quality seals in the old stock metal work which will not have decayed if they have been stored correctly (as long as there is no rust or other corrosion evident.) Only ever use the fluid you are going to use with the seals to refit them... ie if you intend to use silicone fluid use silicone fluid as a lubricant to aid assembly. If you are going to stick with usual glycol fluids then the same applies. Brake systems are so critical to your safety I would not dream of using any type of "grease" to aid assembly even if the seller of the grease says "its ok".... who is driving the car and needs the brakes to work? You or the seller of the grease?
Silicone brake fluid will not cause the seals to break down on its own. If the silicone brake fluid gets mixed with glycol based fluid it "can" but is not certain to create sludge but only as it occurs in use. (Apparently the Silicone fluid rejects any water from the atmosphere that enters through the reservoir and it then becomes separated from the main body of fluid in the brake system. This water then can cause corrosion problems. Regular service will resolve this issue. With Glycol fluids the fluid holds moisture in the fluid which then leads to brake fade as the fluid gets hot during use. Regular service will resolve this issue... there is a common trend here.

New old stock items (even when they are stored in your own garage) can not be relied on to be in good condition they need to be serviced as if they were old items. Silicone fluid is not a "fit and forget" solution any more than any other brake or other hydraulic component. Normal brake fluids require regular service to ensure the brake system remains in serviceable condition.

Service and regular checks need to be made of all critical components and systems as do any components that are fitted into a critical system

[Dieter H. Marschall]

I will butt in here. The most likely culprit is time. All "rubbers" degrade over time and "new old stock" seals and cylinders will have old seals in them even if they have never been used with grease brake fluid or oils. Even if the seals have been stored in dry and dark conditions the likely hood is that the rubber component will have started to degrade... any mineral component of any lubricant will destroy them.

The "win" way to go forward is to use new good quality seals in the old stock metal work which will not have decayed if they have been stored correctly (as long as there is no rust or other corrosion evident.) Only ever use the fluid you are going to use with the seals to refit them... ie if you intend to use silicone fluid use silicone fluid as a lubricant to aid assembly. If you are going to stick with usual glycol fluids then the same applies. Brake systems are so critical to your safety I would not dream of using any type of "grease" to aid assembly even if the seller of the grease says "its ok".... who is driving the car and needs the brakes to work? You or the seller of the grease?
Silicone brake fluid will not cause the seals to break down on its own. If the silicone brake fluid gets mixed with glycol based fluid it "can" but is not certain to create sludge but only as it occurs in use. (Apparently the Silicone fluid rejects any water from the atmosphere that enters through the reservoir and it then becomes separated from the main body of fluid in the brake system. This water then can cause corrosion problems. Regular service will resolve this issue. With Glycol fluids the fluid holds moisture in the fluid which then leads to brake fade as the fluid gets hot during use. Regular service will resolve this issue... there is a common trend here.

New old stock items (even when they are stored in your own garage) can not be relied on to be in good condition they need to be serviced as if they were old items. Silicone fluid is not a "fit and forget" solution any more than any other brake or other hydraulic component. Normal brake fluids require regular service to ensure the brake system remains in serviceable condition.

Service and regular checks need to be made of all critical components and systems as do any components that are fitted into a critical system

Hello,

Thank you very much indeed for your very detailed and informative input. Personally I firmly believe in either buying NOS items, which I revise and then put in storage or in buying used parts, which I refurbish and then put in storage as well. The problem with storage, however, is what product to use for conservation.

As to clutch and brake items I am tempted to believe that "red rubber grease" cannot be too wrong, as this sort of grease is added to Girling and Lockheed repair sets. This type of grease is based on vegetable oil basis.

What do you think? Any input is highly appreciated.

Best wishes,
Dieter - who suffers from about -17° C at the moment. Siberia cannot be much worse...