A silly question...

[rowdytoot]

Hey All,

I've recently replaced a caliper and discs(DBA slotted) on the rally car (gemini), and as a result, lost most the brake fluid in the master cylinder( mainly due to the caliper that was replaced being leaky) ..

I've given the whole system a good bleed, and I had a spongey pedal and basically no brakes at all. Now I'm not getting any air out of it anymore, so I conclude it's a dodgy master cylinder, probably stuffed seals. Now they don't make TX gemini master cylinders anymore, so it's resleeve time- no issue there, just gotta pull it out..

I was messing around on the weekend and decided to rebleed the fronts, and got a little bit of air out of one side, the pedal came good( well as good as a gemini gets ) , and the brakes would lock on when I tried to rotate them by hand, with the pedal down :D

Now thinking i'd done a good thing, I jumped in fired the car up and moved it... no pedal at all... pretty much straight to the floor...

What am I missing?? Stuffed boosters give you a firm pedal with no retardation at all as far as a know, so it ain't that...


Any ideas..??
Dattoman??

Cheers

Rowds

[Spac]

A silly answer....

Banana.

Seriously, it sounds like the MC. The old 808 did this to me - was f$%ked, and just when I'd accepted that the MC was dead, the pedal came good. And not just OK, but "this is right to drive" type of good - Woohoo!

Then it died again, and I was sad.

I figured that there was probably a piece of Datsun stuck in the seal that had been temporarly dislodged, but when I pulled it apart, it was all Datsuned with lots of pitting in the bore.

[rowdytoot]

sweet dude, I shall pull the offending bit tonight and take it to be rekitted etc..
Cheers.

Rowds

[Glenno]

When I bleed my brakes I normally shove a block of wood under the pedal so it can't go all the way down. The idea behind it I am told is to stop the piston travelling byond its regular day to day travel and thus not ripping the seals up on all the rust etc at the end of its travel.

[rowdytoot]

I have a dedicated spirt level that is the right length not to push the pedal too far, and if that isn't available I just grab the g/f :)

I suspect the seals dried out when it was empty and tore when I accidentally went for the brakes when I was reversing it off the trailer... :(

Rowds

[Zac]

Is there a bleed nipple on the master cylinder?

[rowdytoot]

hey zaccy,
kinda, but it's on the underside of the m/c .. which defeats the purpose IMHO...

but I bled it through the outlets like an old corolla.. :p... well one of them, the other is a bit buggered (rounded off) , which is going to make life a little challenging tonight getting it out..

Rowds

[Madhatr]

If you replace the MC and find it doesnt solve the problem, if the vehicle runs rear drums dont forget about the wheel cylinders. If you have a leak somewhere that you cant find, more often than not it is a leak back there letting the air in.

[dattoman1000]

That bolt underneath isn't a bleeder nipple
Its a stop pin screw.
Don't remove it unless you know how to refit it properly without stuffing the master cylinder.

[rowdytoot]

madhatr.. I chucked the car on the trailer the other day and noticed a bit of leakage so I'll replace the wheel cylinders and then re bleed tonight I hope...

Dattoman... kewl, will remember that..

Rowds