Hercules

I'm leaking fluid from between the master cylinder and hydro-boost. More accurately, it's coming out the weep hole on what looks like a 3/4 inch spacer between the master cylinder and hydro-boost. I can't tell if the fluid is brake fluid or power steering fluid. Brakes feel ok and steering seems fine. I think the leak must have started in the last day or two and I lucked out seeing it early. My question is which is most likely to be going, or gone, bad...the master cylinder or the hydro-boost? I'd like to fix this without having to wait for the fluid levels to drop to indicate which part is shot. Thanks for the help!

06RAM2500

Brake fluid and transmission fluid have different odors. My guess would be the hydrobooster is leaking. If it were the master cylinder, you wouldn't have any brakes.

Hercules

Thanks for the quick reply. I think I'm missing something though. You mentioned transmission fluid, but, I thought the 3 lines connected to the hydro-boost are from the power steering pump. So, why did you mention transmission fluid?

06RAM2500

Dodge uses ATF instead of regular power steering fluid.

Hercules

Thanks for the clarification. Unfortunately, it's not ATF. It's Chrysler spec power steering fluid from pre-2002. I think the spec number is 5931, but, could be wrong. I remember reading ATF being used sometime after 2002 and recommendations to use as a replacement on pre-2002 models. When I checked the power steering fluid level, it is not red in color at all.

I think I devised a way to isolate which is leaking. Since the hydro boost always has fluid pressure through it, it should leak when running while sitting in the driveway. The master cylinder should leak while applying the brakes. I plan to clean the weep hole and area around it and do both tomorrow. Hoperfully, one will produce the leak and I can fix it tomorrow. Thanks again for you help and info!

06RAM2500

No problem.

Junk Man

His is a 97 & I haven't checked. 00 FSM specifically calls for power steering fluid. I've changed to synthetic since dino makes noise when cold.

olddodgetrucks

taste it,put a little on your finger and taste it,if it taste like he.. its brake fluid

Hercules

Sorry it took days to get back here...worked through Sunday to finish a job before it started raining here and delay it from being finished. Any way, it turns out the leak is from the hydroboost. Nobody had one locally and couldn't get one shipped in until wed or thurs of this week. So, since I would have to wait to get one in and I can't work on it until next weekend anyways, I decided to order in a rebuild kit and do it myself. Thanks for the help and I'll try to remember to let you know how the rebuild went.

Hercules

Rebuild went ok. The hardest part was getting the hydroboost back in. The studs kept catching on the sides of the holes they go through in the firewall. When it finally did pop in, the brake rod hit the brake stoplight switch causing the switch to break. That was about the extent of any troubles. The important thing is no leaks now. All in all, a simple rebuild, just time consuming.

infidel

Not until '03 and newer.
ATF in the older systems will melt plastic and rubber components.

oldblues

wow now that makes me courious ?

when my hydro boost developed a leek everyone said it had to be rebuilt profesinaly and no kit was avaliable ???

where did you get the kit and howmuch did it cost??

chainzaw

http://mopar.mopar1973man.com/cummin...hydroboost.htm
$25
It's easy.

GuitarJack

Howdy
I am trying to rebuild my hydroboost per Mopar1973man's article.
I have two questions for anyone who has done this rebuild.
1. Does the star spring retainer go inside the cylinder? That is where mine was but the article says to place it on the outside.
2. Does the seal kit include a replacement for in between the master cylinder and the hydroboost? That is where my leak was but I do not see a seal that is the same as the broken one I took out.
Thanks for the help! My truck is stuck until I get this figured out.