The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)
-   The 1960 - 1966 Chevrolet & GMC Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=6)
-   -   Brake vacuum (https://67-72chevytrucks.com/vboard/showthread.php?t=838783)

geezer#99 12-03-2022 12:18 AM

Re: Brake vacuum
 
How much initial are you at now?
What’s your idle rpm?

forestb 12-03-2022 08:36 PM

Re: Brake vacuum
 
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 12-03-2022 09:44 PM

Re: Brake vacuum
 
Quote:

Originally Posted by forestb (Post 9150877)
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 12-03-2022 10:22 PM

Re: Brake vacuum
 
Quote:

Originally Posted by theastronaut (Post 9151210)
I used the pads that came in their disk brake kit.

And those were semi metallic pads?

forestb 12-03-2022 10:26 PM

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

forestb 12-03-2022 10:28 PM

Re: Brake vacuum
 
Quote:

Originally Posted by forestb (Post 9151216)
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 12-04-2022 11:37 AM

Re: Brake vacuum
 
Quote:

Originally Posted by forestb (Post 9151184)
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 12-04-2022 12:41 PM

Re: Brake vacuum
 
If I set my timing according to wha blueprint recommends, what should I set my idle speed to

geezer#99 12-04-2022 03:05 PM

Re: Brake vacuum
 
At whatever rpm your motor/trans are happy at.

Steeveedee 12-04-2022 03:14 PM

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

forestb 12-04-2022 05:43 PM

Re: Brake vacuum
 
Quote:

Originally Posted by geezer#99 (Post 9151534)
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 12-04-2022 05:48 PM

Re: Brake vacuum
 
Quote:

Originally Posted by Steeveedee (Post 9151538)
^ 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 12-05-2022 02:50 PM

Re: Brake vacuum
 
Quote:

Originally Posted by forestb (Post 9135314)
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 12-05-2022 07:05 PM

Re: Brake vacuum
 
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 12-30-2022 11:40 PM

Re: Brake vacuum
 
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 12-31-2022 07:27 PM

Re: Brake vacuum
 
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 03-25-2023 03:43 PM

Re: Brake vacuum
 
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 03-25-2023 06:06 PM

Re: Brake vacuum
 
2 Attachment(s)
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 03-25-2023 06:48 PM

Re: Brake vacuum
 
Quote:

Originally Posted by AcampoDave (Post 9190278)
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 03-25-2023 09:08 PM

Re: Brake vacuum
 
1 Attachment(s)
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 03-26-2023 12:02 AM

Re: Brake vacuum
 
Quote:

Originally Posted by cwcarpenter98 (Post 9190325)
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 03-28-2023 03:13 PM

Re: Brake vacuum
 
Quote:

Originally Posted by forestb (Post 9190362)
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 03-28-2023 03:31 PM

Re: Brake vacuum
 
Quote:

Originally Posted by 88Stanger (Post 9191188)
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 04-21-2023 03:57 PM

Re: Brake vacuum
 
Quote:

Originally Posted by 88Stanger (Post 9191188)
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 04-21-2023 03:59 PM

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


All times are GMT -4. The time now is 11:54 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com