[david-b]

Hey all. 75 Monte Carlo. Replacing the brake booster and resivoir. Tore it all down today and realized that there is a bracket between the booster and the firewall. I'm seeing on Summit Racing there's a bunch and nothing specific for the 75 Monte though. You can see in the attached pics that the bolt pattern on the firewall is close together on the one side than the other. The new booster is a 9". Looking at THESE but seems like the holes aren't even close. Any ideas? Thanks!

[cobalt327]

I don't know if you looked over all the brackets, but there's quite a few to choose from.

Depending on the booster you want to use, the original bracket might work once it's removed from the old booster.

[david-b]

Originally Posted by cobalt327

I don't know if you looked over all the brackets, but there's quite a few to choose from.

Depending on the booster you want to use, the original bracket might work once it's removed from the old booster.

I was going through that same list and they're all close, but all different at the same time. The booster I have has the 4 studs in the same position as the stock on, but just need that adapter to have the right pattern on the firewall. I tried to get the stock one off, with no luck though. Is there a trick? It's the original booster that I pulled off, and everything is rusted into one piece.

[cobalt327]

Originally Posted by david-b

I was going through that same list and they're all close, but all different at the same time. The booster I have has the 4 studs in the same position as the stock on, but just need that adapter to have the right pattern on the firewall. I tried to get the stock one off, with no luck though. Is there a trick? It's the original booster that I pulled off, and everything is rusted into one piece.

You might have to separate the vacuum chamber to access the inside back half of the booster to see what the bracket is held on with if there's no obvious fasteners seen on the outside. I have never done this- so I'm shooting from the hip here.

[david-b]

Originally Posted by cobalt327

You might have to separate the vacuum chamber to access the inside back half of the booster to see what the bracket is held on with if there's no obvious fasteners seen on the outside. I have never done this- so I'm shooting from the hip here.

I had tried to. It looks like the front of the booster is supposed to rotate and then slide right out, but could not for the life of me get it to budge. So I tried taking a grinder to the 'lips' of what seems to be holding the 2 together. Sadly, even after doing that, and then pounding on it... had no luck.

I emailed Summit Racing with the same question and pics, see if they know exactly which one I need. They all look off!

[cobalt327]

Originally Posted by david-b

I had tried to. It looks like the front of the booster is supposed to rotate and then slide right out, but could not for the life of me get it to budge. So I tried taking a grinder to the 'lips' of what seems to be holding the 2 together. Sadly, even after doing that, and then pounding on it... had no luck.

I emailed Summit Racing with the same question and pics, see if they know exactly which one I need. They all look off!

There is a pretty strong spring inside that will tend to keep the two halves locked together, I believe they use a fixture/clamp tool to hold it together when dis- and re-assembling them. You might want to do a search for info on disassembling it if you haven't already- what you don't want is to be hit w/the spring or booster case as it comes apart.

[david-b]

Originally Posted by cobalt327

There is a pretty strong spring inside that will tend to keep the two halves locked together, I believe they use a fixture/clamp tool to hold it together when dis- and re-assembling them. You might want to do a search for info on disassembling it if you haven't already- what you don't want is to be hit w/the spring or booster case as it comes apart.

Buying a new bracket will just be better and easier in my book. Brackets are about $20 on average so no big deal. I need to get one ordered today... have a cruise night on Friday. Would like to have brakes for it.

[david-b]

Just an update and a question to follow. So I bought a bracket from Summit for $20. It was close, but so far. When mounted, the boosters arm going to the brake pedal was riding on the firewall, so it wasn't working. Basically was pushing it up to high.

What I ended up doing was moved the bracket down on the studs so it was sitting lower, on the bottom 3 studs. I had to cut the bracket so it wasn't resting awkwardly on a bump on the firewall by removing the lower bolt hole. Pic is attached, before it was finished sanding and painted. Long story short... everything matches up great (minus 1 bolt not there).

Now the question... I've never really worked with brakes before. When I was pulling the resovoir and booster, I disconnected the lines from it and tried to keep as much fluid in them as possible. When connected the new one up, I filled with fluid and worked the brake pedal. Bubbles came out and eventually stopped. However, with the car on and off, the pedal is soft and doesn't close. Do I need to bleed the lines at the calipers?

[1971BB427]

Did you bench bleed the brake master before installing it? If you did, then you can often avoid bleeding the whole system, but if your rakes are "soft" then you need to not only bleed the calipers, but the whole system now.

[david-b]

Originally Posted by 1971BB427

Did you bench bleed the brake master before installing it? If you did, then you can often avoid bleeding the whole system, but if your brakes are "soft" then you need to not only bleed the calipers, but the whole system now.

I'm going to assume I didn't considering I have no idea what bench bleeding is. Damnit. For future reference, got a link to how to do that?

[1971BB427]

Here's a link I just Googled:
http://autorepair.about.com/od/fixit...ench-bleed.htm

You usually get the bench bleed fittings and hoses with a new master, but seems they've gone cheap now and don't provide them. Most any parts store will have them.

[david-b]

Thanks for the link. Mine didn't come with any kind of bleeder kit. That would have been easier if it did.

My buddy has a vacuum bleeder and we're going to do them all tonight.

[1971BB427]

Should be fine after that. No reason to bench bleed it now that it's been in place on the car. Just be sure to bleed it enough to get any air pockets that are near the master all the way out the end of the system.

[david-b]

Originally Posted by 1971BB427

Should be fine after that. No reason to bench bleed it now that it's been in place on the car. Just be sure to bleed it enough to get any air pockets that are near the master all the way out the end of the system.

So yesterday we bled the brakes with really no problems. All new fluid in the lines, all nice and clear. Taking it for a drive, the brakes are there, but not where they were. I don't know if smaller booster is supposed to affect it this much. The car does stop, but really have to push super hard and even then it's not slamming on the brakes like it used to. Any ideas on this? And I'm 100% sure no bubbles in the lines. 3 big bottles of brake fluid and with a vac pump... was done right.

[cobalt327]

Air in the brake system causes a spongy pedal because air compresses where brake fluid doesn't. If the pedal is hard and takes a lot of effort, you might need more assist. Or the pedal ratio can be changed or use a smaller master cylinder bore. That will decrease effort but increase pedal travel. It's a balancing act.