Brake booster (hydraulic) and master cylinder (1993 P30)

[Racer-X-]

The brakes on this thing are on my "do list." They were scary to drive with. Barely adequate to bring it to a stop, definitely no such thing as an "Emergency stop" within possibility. We drove it home from the previous owner on mostly empty roads on a weekend, and I still felt somewhat unsafe.

Looking at the system, I'm seeing the hydraulic brake booster is leaking fluid (power steering fluid) fairly profusely. It "marks its spot" when you park it. I haven't dug into the brake lines and master cylinder yet. The pedal required a lot of force (like the booster wasn't boosting), and still felt kind of spongey (like there's air in the system or maybe a fluid leak). It's getting a new or rebuilt booster and master cylinder at this point.

Has anyone used Prior Brake Products? That's the rebuilders/service that RockAuto.com offers for these hydraulic booster units and master cylinders. It looks like they want ~$160 for "return and rebuild service" for the hydro booster only, and ~$190 for the same "return and rebuild service" for the booster and master cylinder together. If I understand the process, you send yours in, they replace seals, test and fix anything else and send your exact unit back "remanufactured."

It looks like I need to know a RPO code and/or a "pedal rod code" when I order/send the unit in. RPO codes brings up another interesting question. Where is the SPIDS on this chassis? It's usually in the glove box on most GM Vehicles. I haven't found a glove box in this one, so I don't know where they might have stuck the sticker.

[Racer-X-]

I know it's been a while, but here's the report. I finally got back to this project in mid August. We sent the old master cylinder, hydro booster, and the pedal linkage/bell crank piece as an assembly to Prior for rebuilding. They took a little over 2 weeks to get it back to us (including shipping from Atlanta to Prior in TX and back, which accounted for about 6 days total).

They seemed to do a good job. No more leaks, no more sinking pedal. It seems like they even lubricated the pivot shaft on that big bell crank for us. I took that apart to put some fresh grease in, but it looked like it was freshly greased when I pulled it apart.

Unfortunately, the pedal effort was still very high, but steering effort is also pretty high as well. We took it out anyway for the weekend before labor day, and it drove OK, but it took a lot of pressure on the brake pedal to get the thing stopped. Since the steering is also very high effort, especially at lower speeds, the power steering pump is suspect for sure.

I've ordered a new power (remanufactured) steering pump (and new belts) that should be delivered today or tomorrow. I'll probably get back to it on Monday to install it. Today I'm removing the old power steering pump today. Other than the normal close quarters stuff you get with any engine work on an RV/Van, it seems to be coming out OK.

[colonelcorto]

Please keep this updated. I have an older F53 chassis with scary brakes. I'm starting with having the rotors resurfaced at NAPA, throwing on new pads, and greasing the caliper pins, I might bleed everything while in there as well. I don't have any leaks but the hydro-boost system looks like a PIA. BTW, I have a tag-axle and I think there is a separate brake fluid reservoir in the rear for it.

[Stim]

Have you priced it at your local NAPA?
Sometimes they are very reasonable on brake parts and it's easier to deal locally if there is a problem.

[Stim]

Have you priced it at your local NAPA?
Sometimes they are very reasonable on brake parts and it's easier to deal locally if there is a problem.

[MountainAir05]

After all that then look at the brake cylinders and all lines. If the rubber ones have not been done it past time. If you can not find them then go stainless steel braided from your speed shop. #3 or #4 size.