Brake vacuum

[geezer#99]

How much initial are you at now?
What’s your idle rpm?

[forestb]

I checked my timing today but made the mistake of forgetting to plug the vacuum advance.

16 degrees of initial timing.

33 at 1500
Around 55 at 2500
Blueprint recommends 32-34 at 3500 (or at the point the mechanical timing stops advancing) for their engines. I didn’t feel comfortable taking it up to 3500 rpm

It was running at 600 rpm at idle which seems a little low so I bumped it up to 7.

The brakes are so close to working good. I think the semi metallic brake pads and boots with a vacuum canister will solve the problem.

[theastronaut]

Originally Posted by forestb

I have the cpp drop spindles also. Do you remember which brake pads you ordered for them?

I used the pads that came in their disk brake kit.

[forestb]

Originally Posted by theastronaut

I used the pads that came in their disk brake kit.

And those were semi metallic pads?

[forestb]

I also found out that I have a leak from my axle shaft seal that is probably causing that drum to fail.

[forestb]

Originally Posted by forestb

And those were semi metallic pads?

I have had my beak pads replaced sense the calipers were installed. Is there a way to tell if the pads are ceramic or semi metallic?

[geezer#99]

Originally Posted by forestb

I checked my timing today but made the mistake of forgetting to plug the vacuum advance.

16 degrees of initial timing.

33 at 1500
Around 55 at 2500
Blueprint recommends 32-34 at 3500 (or at the point the mechanical timing stops advancing) for their engines. I didn’t feel comfortable taking it up to 3500 rpm

It was running at 600 rpm at idle which seems a little low so I bumped it up to 7.

The brakes are so close to working good. I think the semi metallic brake pads and boots with a vacuum canister will solve the problem.

So you basically have low initial timing combined with a higher idle setting both of which reduce your idle vacuum.

New pads and brake shoes won’t change how your brakes function.You still won’t have enough vacuum for your booster.

[forestb]

If I set my timing according to wha blueprint recommends, what should I set my idle speed to

[geezer#99]

At whatever rpm your motor/trans are happy at.

[Steeveedee]

^ Right. Do you have a stock converter?, or is it higher stall?

[forestb]

Originally Posted by geezer#99

At whatever rpm your motor/trans are happy at.

I was under the impression from your last post that you thought the idle speed was too high so I was curious what you thought it should be.

[forestb]

Originally Posted by Steeveedee

^ Right. Do you have a stock converter?, or is it higher stall?

I know that when I had a turbo 350 transmission in it I had a non stock converter and that helped the brakes back then when I had a 308. I don’t know what the guy that installed the 700r4 put in it but he is the one who last looked at my brakes and he didn’t mention that as a solution.

[88Stanger]

Originally Posted by forestb

What brand of Hydro-boost did you get?

Damn sorry, I did not see this. I got the universal Breast kit from CPP for front and rear disc brakes. As mentioned, it is not cheap, but stopping is a good thing and being able to stop if it is a small person driving it is also a good thing, one of many reasons why I went with Hydro boost.
More info on my build of the "66 just recently..

[forestb]

I talked to the guy that reset my timing and he used a vary imprecise way of doing it. He said he only set the initial timing at around 18-20 and listened for pinging and drove it around a little and was happy. I am either going to have to do it my self or take it somewhere that will fallow the blueprint directions.

[forestb]

Spent a little time with Steeveedee checking the timing and adjusting the mixture. He figured out that the timing was set at what blueprint recommended and adjusted the mixture so that I have around 16 pounds of vacuum. My breaks are working a little better but have not completely fixed the backing out of the driveway problem. I will probably add a vacuum canister just to give it a little extra help. Thank you Steve for your time and it was fun getting to know you and meeting someone from the forum.

[Steeveedee]

Right on! Nice to have met you, too. If you have time on a non-rainy first or third Saturday, there is a meetup of all kinds of vehicles at the Firestone tire store in Thousand Oaks. I've only made it a few times since I found out about it, though. That's a nice truck that people can appreciate, there.

[forestb]

2 questions

1) on the stock single pot master cylinder are the bolts that connect it to the fire wall horizontal or at they more at around a 45° angle.

2) about 2 years ago I moved the bolt hole location for where the master cylinder push rod connects to the break pedal. I moved it around an inch lower because that is what I read you are supposed to do if you install power disk breaks. That was when I had my old engine and plenty of vacuum. Now that I have less vacuum because of my new engine I was wondering if it would be a good idea to move it back up to the top hole in order to get more leverage. I am trying to not have to push on my brakes as hard because I am trying to heal from a foot injury and don’t want to put too much pressure in that location. My plan is to also install a vacuum canisters.

[AcampoDave]

I think diagonal. Here is left and right sides. You can see the old holes filled in with caulking. Inboard side low, outboard side high.

[forestb]

Originally Posted by AcampoDave

I think diagonal. Here is left and right sides. You can see the old holes filled in with caulking. Inboard side low, outboard side high.

Thanks

Does anyone know of any companies out there make a dual port master cylinder that has that kind of bolt pattern if I want to go back to manual breaks that will work with my front discs and rear drums? I looked on the willwood, pol and cpp websites and either didn’t see anything or didn’t know what I was looking at.

[cwcarpenter98]

On my 63, the original master was horizontal. The brake/clutch master and heavier duty trucks used the angled bolt holes. I don't believe the orientation of the master will change your braking performance.

Have you looked into potentially using a hydroboost system?

[forestb]

Originally Posted by cwcarpenter98

On my 63, the original master was horizontal. The brake/clutch master and heavier duty trucks used the angled bolt holes. I don't believe the orientation of the master will change your braking performance.

Have you looked into potentially using a hydroboost system?

The reason I was asking about the orientation of the mc bolt holes was because I didn’t see any after market 2 pot master cylinders with the angled bolts and it looks like that’s what my truck has. I was more curious about where the rod connects to the break pedal and how that might help change things.

I have looked into the hydroboost system but a couple people on this thread were pretty negative about it and it’s kind of expensive.

At this point I am just looking for whatever will work best without my needing put too much pressure on my foot.

[88Stanger]

Originally Posted by forestb

The reason I was asking about the orientation of the mc bolt holes was because I didn’t see any after market 2 pot master cylinders with the angled bolts and it looks like that’s what my truck has. I was more curious about where the rod connects to the break pedal and how that might help change things.

I have looked into the hydroboost system but a couple people on this thread were pretty negative about it and it’s kind of expensive.

At this point I am just looking for whatever will work best without my needing put too much pressure on my foot.

I have installed 2 hydroboost systems on two different trucks and love the outcome. It is a bit expensive BUT for safety reasons I wanted great brakes and simple operations (referring to not much foot pressure needed to fully operate the brakes) so that if my older mother wanted to drive it, she could stop it.
With all this said, I have recently received a 1940 Chevy Coupe that is way far passed stock, all set up for racing. The brakes on it are a completely different system than I have ever installed. It is using Wilwood Dual Master Cylinders - one for front and one for rear. Then there is a brake pedal mount with a proportioning adjustment built in that allows me more pressure to front or rear and somewhat adjustable. This system was installed due to very low vacuum and no power steering (no fluid pump for the hydroboost). This dual master cylinder system is very cool, fairly simple but just like Hydroboost, it is not cheap.
Just wanted to throw out another option.
I went with Hydroboost for my current project and previous project and love the system.
Just my $.02 worth.

[forestb]

Originally Posted by 88Stanger

I have installed 2 hydroboost systems on two different trucks and love the outcome. It is a bit expensive BUT for safety reasons I wanted great brakes and simple operations (referring to not much foot pressure needed to fully operate the brakes) so that if my older mother wanted to drive it, she could stop it.
With all this said, I have recently received a 1940 Chevy Coupe that is way far passed stock, all set up for racing. The brakes on it are a completely different system than I have ever installed. It is using Wilwood Dual Master Cylinders - one for front and one for rear. Then there is a brake pedal mount with a proportioning adjustment built in that allows me more pressure to front or rear and somewhat adjustable. This system was installed due to very low vacuum and no power steering (no fluid pump for the hydroboost). This dual master cylinder system is very cool, fairly simple but just like Hydroboost, it is not cheap.
Just wanted to throw out another option.
I went with Hydroboost for my current project and previous project and love the system.
Just my $.02 worth.

Thanks for all the input. Do you have a link to the Hydroboost system that you used?

I have seen the other system that you described on an episode of Roadkill Garage.

[forestb]

Originally Posted by 88Stanger

I have installed 2 hydroboost systems on two different trucks and love the outcome. It is a bit expensive BUT for safety reasons I wanted great brakes and simple operations (referring to not much foot pressure needed to fully operate the brakes) so that if my older mother wanted to drive it, she could stop it.
With all this said, I have recently received a 1940 Chevy Coupe that is way far passed stock, all set up for racing. The brakes on it are a completely different system than I have ever installed. It is using Wilwood Dual Master Cylinders - one for front and one for rear. Then there is a brake pedal mount with a proportioning adjustment built in that allows me more pressure to front or rear and somewhat adjustable. This system was installed due to very low vacuum and no power steering (no fluid pump for the hydroboost). This dual master cylinder system is very cool, fairly simple but just like Hydroboost, it is not cheap.
Just wanted to throw out another option.
I went with Hydroboost for my current project and previous project and love the system.
Just my $.02 worth.

I ended up getting a Hydroboost. How did you connecting the the power steering pump return line (non pressurized) to the pump. My hard line that comes out of the pump is facing toward the front of the truck? Do you have any pictures.

[forestb]

Sorry nevermind. I just realized that that line goes to the gear box so it should be facing forward.