190e brake failure - your assistance please...

[ChrisH2O]

So the brakes failed on it last night (only a very small amount of pedal pressure at the far end of the travel) thankfully on a very long motorway slip road and got parked up safely.

I've found the problem but I need someone's help to find the part I need.

There are two small rubber bung/nipples on top of the brake fluid reservoir, these were heavily split and perished. I've zip-tied them up as a get-me-home, and this resolved it.

Anyone know what these parts are officially called and where I could get some? Is this something GSF would stock etc?

I'll try and find a picture...

 

[ChrisH2O]

Can't find a picture, so this is a text only plea!

 

[SQ_W211]

Errm, if you are not sure about the part then maybe locate it in a scrap yard or on Ebay for second hand part. Its very hard to identify without knowing what we talking about, it could be the case that you need a new reservoir tank.

Good Luck

 

[ChrisH2O]

It looks like its a Girling part, number TS Girling 3260470

Anyhow, I've been to the Merc dealership in Leeds and they've found the parts and ordering them in for 9am tommorrow, £2.50 each. Win.

 

[kth286]

go to a main Merc dealer parts dept with your VIN. They will be able to help.

 

[wireman]

If these two parts are on top of the reservoir they are covers on the fluid level sensing switches, as part of your regular vehicle checks pressing down on them should switch on the fluid level lamp.

I cannot understand how their abscence or deterioration could affect your brake pedal since they are there to stop a small amount of muck or more importantly water getting into the fluid, long term this is a major safety risk but with cold brake calipers and just one application the brakes should work ok even if there is serious fluid contamination.

The symptoms of long travel are indicative of one half of the master cylinder failing, this is possibly an ocurrence of one the rubber piston seals in the working part of your master cylinder being over ten yers old and due replacement as a service item. It is not unknown that the seals can fail partialy and alternate between seemingly good and downright dangerous.

Do replace the master cylinder if there is any doubt as to its age, it should not be left to chance since if both halves fail (they are the same age) the total loss of braking will be extremely vexing and possibly lethal.

It is most important to change the fluid after a maximum of two years (MB reccomend 1 year) or all the seals and flexible pipes will eventualy get exposed to the tatty old fluid and become soft and prone to catastrophic failiure.

In my opinion if the fluid level was ok after your near do there is something much more serious wrong than a damaged dust cover.

Sorry to bang on about tired brakes again folks, but I have been involved in two post accident investigations in which tired soggy master cylinder seals were the prime cause of failiure.

A new master cylinder will cost £50 -100, shop around try MB, GSF and ECP.

I would not entertain getting major braking components from a scrap vehicle unless you know the service history of the scrappers braking system components. however your dust covers could come from such a source since they do not directly affect the braking systems functions.

 

[Myros]

Wireman is dead right

don't cut corners with brakes or brake fluid. I can also recommend Brakes International in Rochdale as suppliers of good quality kit.

 

[ChrisH2O]

Thanks Wireman, a really valuble post. The car is going to Scotts Auto Tec in Leeds for a big check over and service this month so I'll make sure they take a look at it. Cheers everyone!

 

[ChrisH2O]

It went in today, and you'll be glad/relieved to know it's had a new master cylinder, all new handbrake parts, a full rebuild of the rear brakes and numerous other things (including a full service)... so I am considerably out of pocket but content that the 190E will stop as well as it goes

 

[television]

Thanks for posting back and letting us know