85 C30 hydroboost replacement?

[prateroad]

It's been a while since I've been on here, I have a power brake booster question. I've got an 85 Chevy C30 with the hydroboost that needs a seal kit installed. Is there any way that brake fluid can get into the power steering system via the hydroboost? I'd also like to know your thoughts on completely removing the hydroboost and installing a double diaphragm booster like they used to put on the C30 before the hydroboost came out. I have no idea why they put the bolts on the inside of the cab, they look like a real pain to get to, especially the upper right side bolt or nut. Any tips on removing that hydroboost for a re-seal or replacement appreciated. This is always my go to place for advice. It's not who you are, it's Who you know. Thanks again.

[SCOTI]

Originally Posted by prateroad

It's been a while since I've been on here, I have a power brake booster question. I've got an 85 Chevy C30 with the hydroboost that needs a seal kit installed. Is there any way that brake fluid can get into the power steering system via the hydroboost? I'd also like to know your thoughts on completely removing the hydroboost and installing a double diaphragm booster like they used to put on the C30 before the hydroboost came out. I have no idea why they put the bolts on the inside of the cab, they look like a real pain to get to, especially the upper right side bolt or nut. Any tips on removing that hydroboost for a re-seal or replacement appreciated. This is always my go to place for advice. It's not who you are, it's Who you know. Thanks again.

Not 100% sure on the brake fluid bleeding over to the hydraulics side of things but I know it can make its way into a diaphragm cannister on a vacuum boosted set-up. If it can for the vacuum set-up, I'd bet it could do the same w/the hydraulic boost.

The bolts are a PITA to access but it only has to be done for the swap. Swapping hydraulic for vacuum is some work but can be done. Besides swapping all the expected parts under the hood, you also need to swap over the correct pedal while you're under the dash (or alter the hydraulic brake pedal) because the stroke is different between the two braking systems. Not a big deal if you're not scared to tackle the other stuff.

Effectiveness? I wouldn't do it on a 'working' truck (one that's still hauling to it's full capacity). But the vacuum brakes work fine slowing a dually down pulling a single open car trailer.

[prateroad]

Thanks for the reply, my main concern would be if the vacuum booster would just bolt up. I thought it would have the same bolt pattern. Is the pushrod the only difference or is the pedal different also? I have a 67 C50 that has 20" wheels and it has a big vacuum booster on it, it's a pretty big vacuum chamber though.. They changed them later to a remote hydrovac that mounts under the cab.

[SCOTI]

Originally Posted by prateroad

Thanks for the reply, my main concern would be if the vacuum booster would just bolt up. I thought it would have the same bolt pattern. Is the pushrod the only difference or is the pedal different also? I have a 67 C50 that has 20" wheels and it has a big vacuum booster on it, it's a pretty big vacuum chamber though.. They changed them later to a remote hydrovac that mounts under the cab.

It's a direct bolt-in swap going from Hydraboost to vacuum brakes on 73-87's. The pedals have different pivot points for the rods so different ratios.

You either have to relocate the pivot bushing on the existing pedal to the correct spot or get a pedal w/the pivot bushing correctly located. Either option requires pedal removal.