Spongy Brakes

[fillander]

Hi, I have noticed recently that when I take my 01 Grand Caravan sport on the highway that my brakes will become very spongy after awhile. This does not occur with typical city driving though. After about 20 minutes of highway speeds I can push my brake pedal almost to the floor. There is very little resistance at first and then it will engage. It is almost like there is air in the system but I don't think so since it would be like this all the time (i.e. the air can't just disappear).
Also in park I noticed that everytime I push the pedal I hear a click in the dashboard. It sounds like a relay engaging, could this have something to do with it? Since it has rear drum brakes I also thought about this being a cause. I am not familiar with drum brakes as all my other cars had disc brakes all around.

[Airjer_]

Do the brakes ever smell hot?

[fillander]

I have never noticed the smell and I probably would but I will pay close attention tonight.

[Bear]

I have this issue witm y '96 and bleeding the brakes always solves the problem (for a time). I finally put some Russel Speed Bleeders on her so it was easier to bleed the brakes. I have new pads and shoes as well as new rear wheel cylinders and yet she still sucks air from somewhere.

[fillander]

Thanks, maybe I will bleed them just to be sure and change the shoes. Any thoughts on the clicking sound or is that normal?

[Spit]

One of the most common causes of spongy brakes is air in the lines, but another good thing to look at is your rear drum brakes. If they are out of adjustment (too loose) there will be a bit of sponginess when applying the brakes...even if your front disc brakes are well adjusted.. It has to do with the brake systems equalizing the pressure. If it takes to much to get the rears to engage, it slows the fronts from engaging. Lots of us fool with our front discs but never mess with the rear drum brakes so it's not unusual that the fronts have been changed 2 or 3 times and the rear drums never touched. These vans like lots of vehicles have automatic adjusters for the rears. Which do their thing only when the vehicle is driven in reverse.

It's an easy non technical thing you can try...take the van to an empty parking lot...drive in reverse and hit the brakes at about 10-15 mph do this over and over.. a dozen times or so. This should get the automatic brake adjusters to tighten up the brake pads to a closer fit to the drum. See if this can help

If that doesn't work you can bleed the brakes..really not as hard as it seems, there is a real simple one man bleeder kit you can get at Harbor Freight or an Auto Parts store for less than $10. I think the procedure is covered in the Haynes Manual for the T&C

Chuck

[fillander]

Thanks for the advice. I actually have a bleeder kit but I think I will try your reverse suggestion. I knew about going in reverse to adjust but not the whole procedure you explained so I will do that next.

[Spit]

It's easy, doesn't cost anything to try and can't hurt a thing as long as you're careful when driving in reverse. That's why an empty parking lot makes sense. Good Luck
Spit

[plymouthsrock]

Does your parking brake have excessive travel? If so, the problem is most likely in the rear.

[Spit]

What you're experiencing could be refered to as "brake fade" After the brakes heat up one of 2 things happens... 1. Mechanical Fade: The drum heats up and expands away from the brake shoe, or 2. Lining Fade: the surface of the lining is heating up and losing it's friction co-efficient i .e. it's ability to grip the drum.

I would try the easy things first..adjusting the rears driving in reverse. Visual inspection of the fronts...(that's easy) 2. bleeding all the way around. Manually adjusting the Rears jack up the rear end pop out the access plug and manually turn the star-wheel till the wheel drags...then back it off a quarter turn or so.

If all that fails...you may have to pull the drums and replace the rear drums...do-able but a lot more involved than the fronts. Get a Haynes or a Chiltons and do one wheel at a time so you can have the one you haven't taken apart yet as a guide to putting the one you've dismantled back together.

Spit

[exalteduser]

Im pretty sure that click you here in park is the safety switch. on mine you cant shift out of park without pushing the brake, that click unlocks the gear lever

[peterjon1]

There's also a chance that a flexible hose is starting to go. They can separate internally, thus blocking the fluid from leaving a caliper, resulting in the brakes dragging.