I have a 2004 DII, brakes are fine overall, a bit mushy but not seriously so.

There does seem to be some leakage (very minor) from the Reservoir. Maybe a cape full in 500 km.

However last evening my pedal went to the floor, the Disco stopped but still nerve racking - I was just out of my driveway. Next press pedal was fine, slow 15 minute drive around the block no issues.

Tried the press pedal test pedal stayed firm.

Having just gone through this with my previous vehicle - I suspect the master cylinder is going.

Any good tests to get a definitive answer ?

 

Try bleeding it first.

 

Thanks that was the 1st thing on my list, but I figured I might as well ask some advice. Stopping is kinda of critical .

 

I think your escapade at the foot of your driveway is fairly definitive. Don't you?
Check all you lines and look to see if there is any greasy slime built up on the underside of the MC and the brake booster.

 

Replace the master cylinder, both of mine were bad. Same symptoms, no pedal and then firmer with each push. If the fluid never got extremely low, no air should have entered the system. Start hitting the bleeder screws with WD40 now, since bench bleeding the master will only get you so far...better to bleed entire system once replaced.

Brian.

 

The master and bleeder are bone dry, used a kleenex just in case.

Re-checked the pedal and it is solid.

I expected a pedal drop again it did not. But having said that I have not had a chance to crawl around underneath and check all the lines.

That is a weekend job.

Are the bleeders a standard size on these ?

 

The bleed screws are M10 X 1.0 X (30 - 35mm).
NEW OE part #: LR015523 OLD #: RTC1115

OR from RA or an auto parts store something like...
> More Information for DORMAN 484151

> More Information for DORMAN 12706

 

A couple quick tips

Get a turkey baster and suck out all the old fluid from the reservoir prior to adding new fluid for the bleeding. This way you are not bleeding with old fluid.

Put the truck on jack stands and after your third go around bleeding, start truck and let it run in downhill decent assistance to help get out the old fluid and bubble prior to the final bleed.

 

Note to self...never go over to Friday Night Disco for Thanksgiving dinner...lol.

 

Thanks all for your suggestions and advice. Looks like a day of truck work over the holidays, at least it should be an interesting day.