Spongy brakes overnight???

[SELfor50]

Turns out that the reservoir only LOOKED full!  There was a kind of high water mark that tricked the eye, while the reservoir itself was empty because of leaks- the right rear caliper needed to be replaced and the right front caliper was rebuilt, and the system bled (of course).  The master cylinder is just fine.

If anyone had a read through all the posts i've contributed to this site, i've done my fair share of 'pretty average' shyte (including f*king up spark plug threads, not connecting the starter motor earth strap on re-connection and spending another 3-4hrs ripping it out and changing it when i didn't need to) 

But dude, something like assuming the resevoir is full by looking at the outside is up there with them!  ...gotta get your hands dirty dude, which means caps come off!

Have you been hanging out with George W there in D.C.? 

All in jest dude, just takin' the pi$$.

Glad it's all working well now mate.   

Cam. 

[mabryt]

Hiya Cam-

Too right- the sad thing is, I am HAPPY to get my hands dirty and regularly do, but just overlooked the obvious.  Maybe working a few minutes drive from the White House is damaging my brain!

Very happy it all worked out in the end.

Best, TJM

[samuli]

Although I guess the problem of this topic is fixed I write my recent experience with the brakes of my 1976 280SE. When I bought the car about a month ago the brakes were already quite weak. The pedal went almost to floor but managed still stop the car. After one heavy braking they weakened sigificantly. Pedal went to floor and only hint of braking was during pushing the pedal. But when the pedal reached the bottom the braking power ended.

Since no leak in the system was detected I suspected the master cylinder. I took the car to a local mechanic who asked me to pump the pedal while he was inspecting the fluid level in the reservoir. He observed that the level was oscillating while pumping. Rising when pushing the pedal. That confirmed the master cylinder damage. We installed a new cylinder and the brakes are now nice and firm with very few pedal travel.

[mabryt]

Hi Samuli,

Good news.  Satisfying to diagnose and correct the problem, yes?  And especially when it's about your brakes!

[samuli]

Yes, it felt good indeed. I don't know how the mechanic did it, but he received a new genuine master cylinder in less than 24 hours. The cost of the part was bit over 300 euros. But, still the satisfaction from nice acting brakes is much more than that...