My dad has a 93 D 250 and today the brake pedal dropped a couple of times while coming to a stop with light braking. The ABS and brake light have been on for about a week now so I guess it's time to do something about this problem before it causes a bigger problem.I'm thinking that it may be the master cyl leaking internally.What else should I check? I called Autozone to get a price and was told that the cyl comes without a reservoir but the truck has a cast iron master cyl and the factory reservoir is not removable. Any recommendations on where to get one for a decent price?

 

I'd check your Mastercylinder for fluid first off... if you haven't already... A line may have blown allowing for it to slowly leak thus causing slushing in a drained cylinder resivoir, which would lead to air build up in the lines?

If it seems like you're losing fluid, check to see if your cylinder itself is leaking then trace the lines. Remember there's a pig of a line that goes from the front of the truck, all the way to the back along the framerail which is kind of hidden curtesy of the fuel tank.

On the bright side, a new master cylinder was only 60 bucks Canadian for me(probably like 5 bucks american ). I think you can get a kit to rebuild it but I'd rather spend the little extra... buy a new cylinder and get a year or two warrenty on it.

I know I've had nothing but trouble with my brakes. I've replaced EVERY line, went through 2 Master cylinders, put on all new routers, calipers, pads, brake shoes, drums, wheel cylinders, brake adjusters and bleeder screws along with a new 100$ brake booster sensor. The worst part was the lines... there's more sections than you think. Finally though, I've got brakes and it was well worth the hastle let me tell you.

Mike

 

The master cyl is full so I'm thinking that maybe there is an internal leak in the MC.How do I check the rear wheel antilock valve? THe ABS light and brake lights are staying on but I did notice that when the pedal dropped upon light braking, the lights went off for a few minutes and then came back on.

 

I'm not overly positive how the antilocking system determines what is what. And sometimes it's hard to get those lights to go away once they do start showing up. I know once u fix your problem it takes so many cycles of the key to get them to disappear, however you can remove unhook the negative battery cable, leave it overnight and it SHOULD reset the whole trucks settings providing everythings working A-OK. Some guys just seem to bypass the whole system and unplug the ABS computer. That's the big black box like thing behind the glove compartment.

As for that antilock valve... when they do go they do mess a few things up... and it does cost some pocket change for a new one. Get a new one if ya like or just unplug the computer. Someone else will throw some imput in here I'm sure.

 

How long has it been since the rear brakes were adjusted? The self adjusters are worthless and the brakes need to be adjusted by hand every now and then. You might be using up all the fluid taking up the slack and causing the brake pressure to drop.

 

I put rear brakes on the truck about 10K miles ago, but I will check and see, certainly would be a cheap fix.Truck still has good peddle though so I'm still thinking there is an internal hyd. leak.

 

How's the pedal at a stoplight? Does it slowly sink or is it solid, but low to the floor. A sinking pedal indicates a leak, a steady pedal indicates a problem elsewhere.

 

a price for master cylinder for me was 40 and they gave me 20$for my old one
that could be your prob maybe you got a bad booster if the pedal goes low and hard and it seems you got no brake that could be it you hear a woush sound under the dash if it leaks wen you press the pedal that is more like 200 if i remember i had to change it on mine

 

Most newer cars come with a removable plastic reservoir so that's why they mentioned that, although if they knew what they were talking about they would've actually looked at the product description at least.
Advance Auto has them for 19.88 Lifetime warranty and most stores should carry them in stock. In Ga they may be called Discount Auto Parts instead, same company. I've had one on mine for 2 years with ney a problem.

 

A few years back I had some trouble with the brakes on my 92. It would stop fine, did not have to oump the master cykinder but the pedel would fall away while waiting at a stop light.

It was the ABS valve. I replaced it and things were ok.

This weekend I'm going to bypass the valve all together, like some have and see if that improves the braking.

Jim

 

I had problems with my brakes bleeding off too. It was the ABS valve causing the problem. The only way I could replace the rear wheel ABS valve other getting a new one from Dodge ( $280.00 ), is have a machine shop make me an adapter out of round stock stainless, ( $ 80.00 ) There are two different size fittings in the brake line that goes into the ABS valve and no one made an adapter for it. The brakes work GTREAT now, but if you try to stop to fast the rear wheels will lock up. I replaced EVERYTHING on the brake system last month. $$$$$$$.$$

 

What happened when the pedal was depressed? i'm having a similar problem with a spongy pedal (occasionally), but more noticable is the jerky response I get when braking from highway speeds. I know I have a leak in the rear drum, but does that explain this kind of bouncy braking? Truck seems like it is only catching every 1/2 sec or so, resulting in a very jerky stop. Brake and anti-lock lights are on, and problem dissappears when I press the pedal harder.
mike

 

I'm not sure about the jerking but, if you have a leak in one of the drums that could cause that. You may have to pull the drums and replace the brakes and wheel seals. My peddle would go down when holding it for a long time. Really bad when I was on a hill with my 5er hooked up.

 

have the guy at the parts store look up a master cyl for a one to and see if its plastic. probably not, alot of the drivetrain componance on the diesel 250's are one ton parts and have been noted in the parts books