Mercedes 308D seized brakes

[kitchenman]

Hi all, not Nissan I know but you may have the answer
My next door neighbour has an old 308D, bloke he bought if off said' now and again the brakes bind a bit, just rock it back and forth and it will be OK' He has had it a year
Well it ain't going nowhere and full power in 1st gear stalls the engine.
He had a look at the master cylinder, layer of simi clear gunge on top a sort of jelly, looks like clear silicon, fluid visible BLACK.
Brake cables both go slack with hand brake off, no signs of levers outside of back plates, so I do not know if that is the problem
My thought was master cylinder and was going to open a bleed valve on rear wheel, I got a bloke coming he said doubting my ability I think based on my advancing years. I have already overstayed my allotted time by 4.5 years.

Is this a known thing, as fluid looks past its prime I thought drain and replace and perhaps new seals, IF I can get the drums off. He borrowed my trolley jack and confirmed the problem is at the back, wheels off ground neither turn, rules out hand brake I guess unlikely both have jammed on
Any idea guys

[macabethiel]

Most likely cause is the brake booster. My mate had a similar problem on his Carlton.
Turns out that they (servo / brake booster) now operate back to front for safety compared to days of old.
The default position when there is no vacuum is brakes full on. When you start her up the vacuum pump pulls off the brakes and when you start to break it releases the vacuum and the brakes work.

Could be the vacuum pump I do not know where they are on that particular model. If the brake booster is full of gunge looks like someone has tried to seal the leak.

Hope this helps.

[briggie]

calipers / pins seized ?

[firebobby]

Originally Posted by kitchenman

Hi all, not Nissan I know but you may have the answer
My next door neighbour has an old 308D, bloke he bought if off said' now and again the brakes bind a bit, just rock it back and forth and it will be OK' He has had it a year
Well it ain't going nowhere and full power in 1st gear stalls the engine.
He had a look at the master cylinder, layer of simi clear gunge on top a sort of jelly, looks like clear silicon, fluid visible BLACK.
Brake cables both go slack with hand brake off, no signs of levers outside of back plates, so I do not know if that is the problem
My thought was master cylinder and was going to open a bleed valve on rear wheel, I got a bloke coming he said doubting my ability I think based on my advancing years. I have already overstayed my allotted time by 4.5 years.

Is this a known thing, as fluid looks past its prime I thought drain and replace and perhaps new seals, IF I can get the drums off. He borrowed my trolley jack and confirmed the problem is at the back, wheels off ground neither turn, rules out hand brake I guess unlikely both have jammed on
Any idea guys

If the fluid is black,it sounds like it's ancient or the seals in the MC are breaking down, new seals and fluid will at least rule that out

[kitchenman]

Thanks for the input guys, he must be a man of money, he has booked it in at a Mercedes garage to have it fixed "properly"

[macabethiel]

Asked at work they asked can you push the car when the handbrake is off and does it lock up the brakes when you start the engine. They thought culprit if brake fluid has not been changed regularly is the ABS pump block assy.

Be it Brake Booster / Master Cylinder or ABS block you looking at £1k plus to fix !!!

[kitchenman]

Thanks for feedback, I will post what it was if he updates me.