Dodgy brake master cylinder

Rich@rdS

Rich@rdS

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Argghhhh!! I'm not a happy chappy. I've discovered that the brand-spanking new master cylinder which I installed last January (2003) has now started seriously leaking. Check out the pic.

PC250005a.jpg

Surely these things are supposed to last longer than a year. Could I have done something to it when I installed it that would cause this leak? It simply bolted on, it didn't look like it needed any special treatment.

I'll be pretty pi$$ed if I have to go and buy another one, I don't suppose I could go back to where I bought it and get a warranty replacement or something.

No more leaks! Argghhhh!! :moon:

Cheers,
Richard

Edit: sorry, the pic should work now.
 
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Can't see the piccy :cry: :mallet: but did you clean everything well & change the fluid when you installed it?
Nothing like grit, shit & abrasive metal particles to take those things out.
If it's a type you can dismantle, usually a new kit and a light hone will get you out of trouble.
As far as cleanliness goes when working on those things goes, it's the kind of job you'd expect to do on the dining room table; wives & mothers don't see it that way though!! :eek: :mallet: :burnboun:

Alan S :adrink:
 
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I have had a brand new master cylinder faulty when I installed it - couldnt bleed it, and took a while to figure out what was wrong, as I considered it the last thing to be wrong :rolleyes:
Apparently sometimes they will sit around in warehouses, ships etc for a few years sometimes, which can dry out the seals and stuff them!
Luckily I had bought it from Carrevele and Ken (legendary bloke :headbang: )happliy swapped it for a fresh one that was fine.
 
Thanks for the replies. I bought mine from EAI, and when I took out the plugs from all the holes there seemed to be a light oily substance inside so I think it was still "fresh".

Alan, I cleaned out the fluid reservoir and the tips of the brake lines as best I could. I couldn't see anything else that needed cleaning. I think I emptied out the excess oil from in the cylinder before installing it. And yep, I used fresh fluid to refill the system and bled it from all four calipers.

How would I go about "honing" it if I could do it myself? My mum doesn't mind me using the dining table for car-related activities - I've just got to remember to stop using the good teatowels to protect it... :D

Cheers,
Richard
 
You can get a proper honing tool that fits to a drill but in the past I've used a very fine wet & dry paper (800 - 1200 grade) and thoroughly cleaned any traces of carborundum away before reassembly.
Honing is only necessary if there's scores or wear, if however as Haakon suggests it could be simply hard dry rubbers, then simply stripping, cleaning and most importantly, soaking the replacement components in brake fluid (plays up hell with the French Polishing if you get any on the table) :mallet: before reassembly should be all that you need.
I wouldn't get too excited as if this is the case, the last time I did a similar job on a Mazda was in about 1996 & it's still going OK. :D


Alan S :cheers:
 
Richard, you can buy a brake cylinder hone from any car parts & accessory joint for about $10-15, and it's driven by an electric drill. It's a flexible shaft arrangement with two or three small curved profile grind stones attached on the end that can be expanded to fit the bore of the cylinder. I'd say, though, that yours would need the absolute minimum honing - in fact, I'd only use 800/1000 grit wet or dry (carborundum) paper wrapped around the honing stones (which is what I do to finish a cylinder anyway after I've used the stones bare). Use a lubricant like brake fluid. I reckon your seals had gone off but the bore should still be OK. Make sure you clean it out really well with degreaser or similar, then in a bucket of very hot soapy water, then metho or a similar volatile solvent (eg. brake cleaner) so all the water dries up. Then use brake fluid or rubber grease to assemble again with new seals.
Stuey
 
Geez you guys are great, there certainly are some very cluey people around on here! :headbang:

Thanks for the detailed instructions, I'll look into getting a seal kit and a honing tool/sandpaper over the weekend. I would never have thought it could have been something I could do myself, but I'll give it a go and let you know how it turns out.

Oh, and our table is also French polished - got to remember to be careful... :D

Richard
 
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