A brakeless 6.9

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grant v

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This was an interesting experience. I went through to Johannesburg (about 60km from Pretoria) on Saturday morning to fetch a waterpump, and suddenly, while braking for a red light, the brake pedal hit the floor board. The rear brakes, fortunately, still worked, but locked up and there was a hairy moment while the 6.9 slid across the line almost into the intersection.
I thought that the pads were stuffed, as the warning light had been on for a while, but (after a change of underwear) I managed to gently get the car to a Kwik Fit close by, where they changed the pads for me. But there was no difference. So at 60km/h, lots of following distance and much anticipation, I made it back to Pretoria on the highway.
It was white knuckle stuff, because, even at idle, a 6.9 wants to leap forward with all it's Newton-Meters. Thank goodness for dual circuit braking systems and credit needs to go to the 6.9 engineers that this behemouth can still be stopped on the rear brakes alone!
I've now put new seals into the master cylinder, but still need to bleed the system, so we'll see what happens. Frustrating, as I had the master cylinder professionally reconditioned about three years go.
 

s class

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Well, glad to hear you got it home in one piece - but there's your problem - professionally rebuilt..... Self-built is always better :rolleyes:
 

Styria

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Hi GrantV, the rebuilding of the master cylinder has been previously discussed elsewhere. My brake man refuses to do Mercedes units as he reckons they cannot be done properly - maybe he just doesn't want to bother as he always suggests that new would be far better.

I am not sure of the price of a new unit nowadays, but that would be my preferable option. Luckily enough, I also have some tested spare units on hand that would always get me out of trouble. Glad that in the end everything turned out alright for you. Regards Styria
 

s class

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In the last couple of years I've bought new master cylinders from the dealer for the 450SL and for trusty rusty. In each case, the price was around ZAR1500 ($200 to $225), and the results perfect.
 

Michel

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Hi GrantV, the rebuilding of the master cylinder has been previously discussed elsewhere. My brake man refuses to do Mercedes units as he reckons they cannot be done properly - maybe he just doesn't want to bother as he always suggests that new would be far better.


Time to change brakemen Styria
 
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grant v

grant v

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I got the master cylinder reconned by Wingate in Johannesburg, who I've had lots of dealings with in the past. They re-sleeved a number of master cylinders and other components for all my other cars, which haven't given any problems before. Maybe this is the exception more than the rule.

I'm not sure about that warning light - the sensors on the pads were still ok and the brake resevoir was still full??
 
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