Brake oil

[lgr]

Hellow all !

I have one doubt: What is the indicated brake and clutch oil for a 1980 280SL? The regular DOT 4 (yellow) ot the DOT 4 ATE (Blue). The cap of the reservoit says BLAU and my mechanic tell that I sould use this one (blue) otherwise the system can be seriously damaged!

Can anyone help me on this (urgently), please?

Thanks in advance for your cooperation

Luis

[waqas]

Not really sure what the difference is, but I doubt you'll go wrong using DOT 4 ATE (blue). The mechanic probably knows what he/she is talking about.

[Allenh]

Brake fluid.  I decided to use the silicone brake fluid for my restoration.  (it is blue)  This product is minimally hydroscopic and will resist rusting better than the other fluids.  There is some discussion regarding the moisture absorbed by one of the other newer fluids, but I cannot recall right now.  Part of my research on fluids seemed to indicate as much, but I don't remember all the details.  Remember, most of our Pagodas sleep all winter in a warm garage.  Rust never sleeps.

The chief "professional" gripe about the silicone fluid was its boiling point and warnings of soft or spongey pedals would be the norm.  I have run this fluid for a year, it is still clear without ANY signs of rust and I drive fast and have to stop,lets say, firmly from time to time and I have not experienced any performance issues.  Remember that it is not compatible with conventional fluid so care must be used to fully cleanout the old fluid from the system.

This fluid will also work in the hydraulic clutch system and using the same fluids in both systems is imperative since the clutch bleeding instruction recommends using the driver's caliper fluid to feed the slave cylinder to purge the air through the reservoir, and thus fill it.

I could dig up the article if you feel it is important.

Does this help at all?

Allen

[Benz Dr.]

The thing with DOT 5 is that it won't absorb moisture. This might sound like a good thing but in systems that are somewhat open to the elements it's not so good. Normal brake fluid will take up moisture and keep it in suspension within the fluid. Slicone fluid won't take up moisture and certain areas within the brake lines may rust out from the inside if water
 ( moisture ) lays there for extended periods.
The main difference between DOT 3 and DOT 4 is how much heat it can withstand in the braking system. DOT 5 with take the most.

Anyone who tells you ordinary brake fluid with do untold harm to your clutch or braking system doesn't know what they're taking about and I'd be inclinded to question them a bit. It's is why all brake fluid gets flushed out and replaced whenever a car comes to me for service - I'm getting rid of any moisture in the lines or calipers. Brake fluid isn't exspensive and acts as a lubricant. Think of it like changing your oil where you get rid of things in the fluid that shouldn't be there.

I don't ask you, '' Do you want your brake fluid changed? '' I just do it. While the wheels are off and I'm inspecting the front end and steering gear it doesn't take that long to do and takes less than a litre of fluid to do everything. Cars that have regular brake maintainance just about never have any problems The pads, rotors and master cylinder last a lot longer.