by matthewh » Sun Apr 14, 2013 10:49 pm
So lately I have been having a couple weird issues with the brakes on my '93 W350 dually. For awhile, the Parking and the ABS light would come on, usually at low rpms, and disappear at high rpm's, figured a ground issue, just been waiting for all the evil snow to go before fixing it.
Well I ventured to the U.P yesterday to retreve a new engine to swap into my M37. After 3 hrs of seat time, finally decided to exit and stretch. As I slowed to pul off into a gas station, I noticed the brake pedal was hard, almost to the point of standing on it to stop. Got out, checked everything under the hood, no loose hoses, fluid good, no leaks, etc. Climbed back in, and pedel was great, worked like it did when I got the truck, nice, responsive/touchy, good brake pedel feel. After another hour of driving, slowed down again for a turn, same thing, hard pedel. Let off, downshifted, tried pedel again, great pedel, almost kissed window.
Since then, the Parking and ABS light stay on constant, and the brake pedel feel is a gamble. Even short drives threw town, or light to light offer either hard pedel or great pedel.
The vac lines look good, but I know they can deteriorate inside, causing similar issues. Is the ABS valve to blame? Did notice this winter, when the ABS worked on slippery roads, it would hold the rear brakes locked for a sec before rolling again. I own 3 first gen's, and this one has by far the best brakes of all and I would like that face meets window feeling back again.
Thanks
'93 W350 5spd Getrag, 4.10 gears, 83k miles and counting, Mods: LPPP AKA Ma Dually
'54 Dodge M37 6.2/700R4/205, 5.89 gears, WC rear axle