Brake Fluid Low.......

[smartlover4evr 0]

Just thought I'd share something I thought was kind of interesting. Maybe you all know this but it was new to me. My hand brake light hasn't been working for the past 8 months. When it started to fail, it would work occasionally, and then it just stayed on all the time. I didn't think much of it as I know there is a sensor under the handbrake that can break (pardon the pun), and it will just cause the light to stay on all the time. No biggie. Last night however, I noticed my brakes were going right to the floor. I made it home fine, as I still had lots of braking, but it wasn't as good as it normally is. I checked the brake fluid level, and it was well below minimum. I went to the store (in my other car of course), and picked up some DOT 4 brake fluid, filled it to the max line, and then, the hand brake light went out. It's unfortunate for me, because if I had caught it earlier, I wouldn't have to have my brakes blead. I also didn't think anything of this light because my brakes have been fine, and just as touchy as they have always been, with barely any travel before the car comes to a stop. Anyway, I'm glad it's nothing more major than that, and that I caught it before it got too serious. If this has already been discussed, I apologize and feel free to remove it.If not, hope I can save some people some trouble.

[smart142 605]

That's a good reminder for people to check the brake fluid level.Last week I was working on a smart and had a heck of a time removing the filler cap. Very awkward to get a good grip on it.

[smartlover4evr 0]

I didn't even get into how long it took me to get that cap off! Haha. I poured just a little hot water over it to loosen it up, and it came right off. I just have to wait now to get into a garage. I think I'm going to skip MB this time and take it somewhere else. Anywhere should be able to bleed brakes I'm assuming. I'm kicking myself for not checking sooner. Could have saved some time and $$$$$.

[Alex 21]

I believe that once air enters the system, you need to cycle all the fancy electroniccy thingamabobs ABS components in a specific sequence with an MB compatible computer program. A flush of the old fluid can be done the old-fashioned way although a more thorough flush is possible with the computer, but once air enters it pretty much has to be done electronically.

Any good Mercedes independent should have an appropriate system.

[MikeT 744]

Also: investigate the source of the leak. My guess: rear wheel cylinder(s).

[smartlover4evr 0]

Thanks guys. Obviously I'm going to let it sit, and I'll see if I can find the leak. That being said, and idea how much we're looking at if there is a leak? Ballpark is fine.

[Leadwing 565]

People who read this thread will certainly correct me if I'm wrong, but since brake fluid is hygroscopic (attracts water) it's a good idea to swap out (bleed and refill) the fluid once in a while anyway, regardless of an existing leak or not. I remember someone saying five years is a good time frame to follow. Those who are more mechanically-minded will no doubt chime in with a more accurate time frame to follow.

[CANMAN 23]

New brake fluid is a clear straw colour, as it ages it turns reddish brown and if you let it age long enough a coffee black colour.Unlike wine it does not get better with age.Change it every 3+ years when it gets a darker colour.Ditto on having to have a star machine to open the ports in the ABS controller to do a proper flush and get all the air out.Canman

[smartlover4evr 0]

So the car's been parked for about 24 hours now and I'm not seeing anything leaking on the ground. I also checked the fluid level again and it doesn't seem I have moved. I'm going to leave it for another few days to see if I notice any slow leaks. I did notice while I was looking under the car, some black sludge on the bottom of the engine. I remember reading about this in another post but can't seem to locate it. Should I be worried? Could this be oil? I also checked my oil level and that was fine too. Seems to me little smarts don't like to sit for a long cold winter.

[CANMAN 23]

I did notice while I was looking under the car, some black sludge on the bottom of the engine. I remember reading about this in another post but can't seem to locate it. Should I be worried? Could this be oil? I also checked my oil level and that was fine too.

As long as your oil level in the engine is fine don't worry about oil on the engine.It's "normal" for the cdi's to have a bit of oil drip out of the intercooler, it's from the crankcase breather.Just make sure you don't go over 2/3rds on the crosshatched area on the dipstick and try to avoid short trips to minimize the amount that leaks out.Now as to your brakes.Looking for puddles under the car just won't do.You have to remove the rear wheels and drums and inspect the brake pistons for leaks.If you can't do it yourself any half decent mechanic can do it for you. Just don't go to Cdn Tire or Walmart, I said half decent mechanic.Canman

[MikeT 744]

Rear wheel cylinders are cheap, but if te rear shoes have been contaminated with it, they will have to be changed too. The oil on the engine could be the early signs of a leaking intercooler, if it's on the driver's side.

[Alex 21]

As the front pads wear, fluid level will drop. Because the rear shoes self-adjust and wear so very slowly, they don't affect the fluid level to any noticeable degree. I just mention this because if the front pads are due for service and you top the fluid right up, it will overflow when you retract the calipers to replace the pads. If the fluid is low enough to be drawing air in, you have a leak and most likely spot is rear cylinders indeed. The reservoir is large enough to run pads right down without dropping below minimum assuming you started at max. Look for wetness around the inside of the drum and backplate, but it can be leaking without external evidence, you have to pull the drums to verify. The pads, rust, dirt and dust can absorb a lot of fluid before it works its way outside. Other likely spots are at the master cylinder and the ABS components, I think any leaks there would be caught up on the belly pan.Edit: Considering the cheapness of a fluid change, the expensiveness of ABS components and the addition stress ABS puts on fluid, I prefer a four year/100K change interval. Rotors will generally go two pad changes, with my mileage and driving habits I just change fluid and rotors together. First change was at 3 years and 105K, second will come next year.

Edited April 24, 2012 by Alex

[MikeT 744]

I've had the green car's fluid changed twice already and the white one once. Cheap insurance.

[smart142 605]

Rear wheel cylinders are cheap

MB sells them for $183(+tax) the pair. Not cheap in my books.

[tolsen 630]

Original Bosch wheel cylinders for the 450 cost around 30 pounds each in Europe. Aftermarket wheel cylinders are available for as little as 10 pounds each. Beware that Smarts with ESP require the larger 22.2 mm diameter cylinders. The smaller 17.5 mm diameter cylinders are for older Smarts with Trust + and no ESP.

A few links:

http://www.mister-auto.co.uk/en/wheel-brak...v8978_g277.html

http://www.brakepartssuperstore.org.uk/con...-uk/d10981.html

Regrettably above companies do not appear to ship to Canada but it does no harm asking.

Brake Parts Superstore also sell Budweg repair kits for the front callipers. Smart has a repair kit as well but it is incomplete and slightly dearer. Only comes with one slide pin seal and no piston seal. Budweg's repair kit contains all elastomers.

[MikeT 744]

Europe is the place to get them, obviously

[smart142 605]

That's true, But most people will discover they need a set when they they break off the bleeder screw.That happened to me last week. Then the easy out broke off. Couldn't drill it out so I called the dealer and discovered the price.Luckily for me I have a parts car and could finish the repair that day. ''30 pounds each in Europe.'' Is not cheap. That's probably $60 each by the time you get it to Canada. More than double the cost of a regular wheel cylinder.Remember that the wheel cylinder are not interchangeable. There is a left and right.

[tolsen 630]

In most cases all you need to is clean the wheel cylinder and reassemble with silicon grease and stainless steel bleed nipple.