Replacing Hydro Booster

[gmenor]

I am replacing the hydro booster for my truck. It is leaking toward the rear joint. Dealership wants $790.00 so I went to NAPA and got a Cordone Pro Tech. There are two return line fittings, one connects to the one of the steel brake lines and the other bolts to the top of the the body held in by a 5/8 nut sligthly to the rear. The 5/8 nut on the Cordone has a hole but not topped to receive the return line. NAPA called Cordone and said that the return line is no longer needed. Questions I have is will this set off any codes and do I simply plug the return line? Second question is a no brainer. Has anyone used Cordone before and what was the results. Thanks in advance

[DmaxMaverick]

Cordone was good.....20+ years ago. Very questionable since.

There should be NO return line from the brake lines. The master cylinder and brake lines are COMPLETELY isolated from the booster. The only things they have in common are the mount and pushrod. The booster should have 3 lines: One high pressure inlet from the pump; one high pressure outlet to the steering box; and one return line to the pump. Get the right booster. www.gmpartsdirect.com (http://www.gmpartsdirect.com) or www.rockauto.com (http://www.rockauto.com) would be good places to look.

Which "rear joint" leak are you referring to? The "rear joint" would be the firewall, which will usually leak inside the cab. If you are referring to the joint between the master cylinder and booster, the leak is usually brake fluid, and means the MC needs replacement. Verify which fluid is leaking. If you have PS fluid leaking there, then the booster front seal is leaking (the rarest of booster leaks). They usually leak around the accumulator, or out the rear (and onto the floorboard).

[gmenor]

DmaxMaverick,
It is leaking where the body bolts together. Exploded view shows almost a figure 8 O-ring. My rear brake fluid resevior was low when I checked it. It did not come from the resevior. I pulled out of the parking lot and notice I was leavng a good size trail. When it came out is was dumped pretty quickly. It happened I was backing out and there was no indication of brakes going soft (then again I wasn't paying too much attention).

[DmaxMaverick]

If it's leaking enough to leave a trail, that's a lot. The fluid volume of the system is small, about 2 qts. total. With that much of a leak, you should have noticed power steering loss before brake boost loss, and loud pump noise (whine/growl).

If the HB unit is leaking at the housing split, it is bad. Replacement is the only option.

[gmenor]

DmaxMaverick,
No power steering loss or whining at all. I got the Cordone HB amd I just might go ahead and gut to rebuild the old one. At this point I do not want to put the Cordone HB in and find out it does not work.

[DmaxMaverick]

I wouldn't recommend that. These are very difficult and seldom successful to rebuild DIY, even in a good shop with the correct overhaul kit and tools (special tools). I've done quite a few of them and have about a 50% success rate. Many of the internal valve parts are not available to any other than commercial reman's. In the end, it would have been less expensive to just replace with the GM units. Add to that, the "new" unit you have will probably not be compatible with the old. If they went so far as "eliminating" a port, no telling what other changes were made. The aftermarket units (such as Cardone) are not the same as the original GM-Bendix units, internally. The parts don't interchange, and the only retail-available overhaul kits only work on the GM units. If this is a "new" casting, it's probably not a "locally acquired" cast, evident by the missing return port and explanation that it is "no longer needed".

Save yourself some headache, and just get the correct unit. GM reman's are 100% better than any other's "new".

If your leak left a trail and you didn't lose steering or brake assist, I'd suggest looking for another source for the leak. It only takes a loss of a few ounces before the pump starts to complain.