Valve adjustment question on sbf 302

[barnett468 418]

28 minutes ago, signorc said:

Nothing. I just found ot broken a few days ago.

the rod in the booster they sent to you is the one that broke?

 

[signorc 31]

Yes. If you go back on this thread a few pics you'll see the broken piece and the the one ai made

[dcm0123 15]

2 hours ago, signorc said:

Hello,

I can't compare the piston depth cause I only have 1 mc.

As I removed the mc to check the clearance....the bolt I made was bent.  I made a new one of 8.8 steel grade.  adjusted the pushrod to .015 clearance but it still takes too long to come to a complete stop.

I have a single diaphragm.  this is what they sent with the kit.

I have 17,5 to 18" Hg of vacuum to the booster.

the 2 pivot points that you see in the second picture was done by my first rod. when I saw the rod was broken in half I crapped in my pants knowing I could have lost all braking!

Tomorrow I'll compare the brake pedal feel with and without the vacuumed booster.  This sucks cause it was a kit that was sold by SSBC and I took for granted they would have sent me a compatible kit :(

Vacuum you have is good.

Increase the rod clearance to .125 and see if it helps.

Below is a link to a good overview how a power booster works. It also says a way to determine if your power booster is bad on slide #39. Failing this test could also be caused by not enough rod clearance so if you fail, increase clearance.

 

 

 

[aslanefe 333]

If the original rod broke and the one you made is bent, I think there is something wrong with the booster that is causing the rod to bind and bend.

[signorc 31]

I sent the pic to SSBC to get their thoughts. I'll follow up as soon as I hear sm.

I've tried all kids of lengths (shorter and longer than .015") on the push rod....no change in the braking

[barnett468 418]

Did you try it with and without vscuum to the booster.?

If you start your engine for a minute then turn it off and slowly remove the vacuum line going to the booster, you should hear a hissing/sucking noise for a few seconds. If you fo not, there is a vacuum leak somewhere or the one way valve the goes into the booster is leaking.

[signorc 31]

Hi Barnett, no not yet.  Yesterday I removed the oil pan to change the rear main seal cause it was leaking.

Tomorrow I'll add the oil to the engine and start her up to verify the booster working

[dcm0123 15]

Bearing looks to be good condition.

Let us know how you make out when you run the test with and without vacuum.

[barnett468 418]

11 hours ago, signorc said:

Hi Barnett, no not yet.  Yesterday I removed the oil pan to change the rear main seal cause it was leaking.

Tomorrow I'll add the oil to the engine and start her up to verify the booster working

ok, xlnt, that rear seal is such a dirty and pain in the azz job to do with the engine in the car.

[signorc 31]

Update.....

The one way valve on the booster works properly.

When i compare braking the car with and without the booster...... the booster does help me stop the car a slightly better.

When I start the car with my foot on the brake pedal, it does sink a bit (test for page #39 on dcm powerpoint instructional).

 page #40 of the instructional, i don't underatand when it says "there should be 2 or more power assisted brake applications".  What do they mean by "applications"?

To follow up Barnetts suggestion.....when i remove the vacuum hose from the booster after having started the car for a minute and shut it off.....there's no hissing or suckling sound at all.

[signorc 31]

does it matter if I bleed the brakes with or without the engine on? I've always done it with the engine off

[aslanefe 333]

2 hours ago, signorc said:

does i don't underatand when it says "there should be 2 or more power assisted brake applications

Does it matter if I bleed the brakes with or without the engine on? I've always done it with the engine off

After you turn the car off, if the booster is not leaking, you will have softer brakes if you brake 2-3 more times due to the vacuum saved in the booster. With 2-3 more brake applications, booster will consume the saved vacuum and you will have harder (no vacuum boosted) brake.

Does not matter if the engine is on or off for bleeding the brakes.

If you do not hear a hissing when you remove the vacuum hose from the booster after turning the engine off, I would think that you have a leaking booster which needs to be replaced or repaired. There may be brake specialists that can rebuild boosters in Italy.

[barnett468 418]

Yes, if you run the engine for a minute, then turn the engine off and do NOT push on the brake pedal, and there is no hissing sound when you remove the valve, and the valve is definitely good, your booster then definitely has a leak, which will reduce its effectiveness.

This does not mean that you will have great power brakes when that particular booster is not leaking. They will be better but it may or may not make a big improvement, if it does not, a more powerful booster may be necessary.

 

 

 

 

[signorc 31]

Ok. So we've determined that the booster has a vacuum leak then.  Time to search for a brake specialist during a lockdown lol

[dcm0123 15]

Did you verify the hose is not plugged?

Here is a new booster for $85 in USA. Not sure if they will ship to Italy. Comes with rod and check valve.

They do no have the dual diaphragm unless you buy complete kit, only 9" single model. On this website the only one with the dual diaphragm is the manual transmision version, says single 9" is for automatics.

https://www.cjponyparts.com/cj-classics-brake-booster-bendix-style-9-black-1967-1969/p/BOOSTER6/

If you are doing a conversion from manual to power brakes, the brake pedal is supposed to be changed as well. Possibly because the linkage is different. See the above website.

[signorc 31]

so here's the question of the day.... how can I know which m/c I have? if it's for power disk or power drum....

for example on macsautoparts.com:

1. https://www.macsautoparts.com/ford_mustang/ford-mustang-master-cylinder-new-dual-chamber-for-manual-drum-brakes.html

2.  https://www.macsautoparts.com/ford_mustang/ford-mustang-master-cylinder-new-dual-chamber-before-7-2-1972-for-power-disc-brakes.html

3. https://www.macsautoparts.com/ford_mustang/1964-1969-mustang-ford-style-teardrop-master-cylinder-disc-drum-1.html

they look identical but how can I tell the difference?

[signorc 31]

This is what I have:

1. a 1969 power brake pedal (5" from pivot point to pedal pin)

2. am/c with a 1" bore (I don't know if it's a power disk m/c or a power drum m/c)

3. single diaphragm booster with a teardrop eye for the pedal pin

...fyi take a look at what mustangsteve says about boosters and pedals for 69s

[aslanefe 333]

Here are couple videos that might help you.

https://m.youtube.com/watch?v=MbW_v_DdEuU

https://m.youtube.com/watch?v=PGO0aWJkrmo

[signorc 31]

thanks. see them but they dont answer my mc question on how to distinguish a disk mc from a drum mc

[aslanefe 333]

Drum mc should have a residual pressure valve at the mc outlet (that goes to the drum side) under the flare whether it is power or not. Drum mc generally have small reservoir. That is why disc drum mc usually have one big, one small reservoir; big for disc, small for drum side.  Don't know what bore size is for a factory power disc/drum mc.

Those videos may help you figure out why your push rod is breaking/bending; wrong pedal for the booster might be the cause.

[signorc 31]

luck has it that a friend here in Italy has a new 8" booster that he ordered from CJponyparts a while back and never installed it cause he got a Wildwood kit.

here are a couple of pics and the link to what he has.  any thoughts? not an original Bendix but I think it'll be better than my 9" single diaphragm, right?

https://www.cjponyparts.com/master-power-brake-booster-conversion-kit-manual-transmission-1967-1970/p/BBCK3/

[barnett468 418]

1 hour ago, signorc said:

luck has it that a friend here in Italy has a new 8" booster that he ordered from CJponyparts a while back and never installed it cause he got a Wildwood kit.

here are a couple of pics and the link to what he has.  any thoughts? not an original Bendix but I think it'll be better than my 9" single diaphragm, right?

https://www.cjponyparts.com/master-power-brake-booster-conversion-kit-manual-transmission-1967-1970/p/BBCK3/

 

 

"When I set it up the original booster was bad so they replaced it.  They supplied me the current set up (not to say that they couldn't have made a mistake)."

Basically, an 8" dual diaphragm booster will provide more fore than a 9" single diaphragm. Since yours is leaking, it may work ok if you get it fixed, however, if your friends booster is not so much longer that it will cause your master cylinder to hit the shock tower, then you might just want to try that one first, plus from the photo on cj pony parts, the brake rod looks bigger/stronger.

 

1. Did your car have disc brakes originally?

2. Are you saying the new booster in the kit you bought from them was bad so they sent you the booster you now have which is aso bad?

3. Is your current booster a single or dual diaphragm?

4. Is your current booster, longer, shorter, or the same length as your friends?

5. Is your current booster lager, smaller, or the same size as your friends?

6. Is the brake rod in your current booster, bigger, smaller, or the same diameter as the rod in your friends booster?

6. Do you have a drum brake pedal or a disc brake pedal?

 

 

 

[signorc 31]

1. Did your car have disc brakes originally? No. I bought a conversion kit with Granada spindles from Mustangs Unlimited in 2002. they shipped me  a SSBC kit.

2. Are you saying the new booster in the kit you bought from them was bad so they sent you the booster you now have which is aso bad? Yes

3. Is your current booster a single or dual diaphragm? single

4. Is your current booster, longer, shorter, or the same length as your friends? mine is shorter cause it's a single diaphragm.

5. Is your current booster lager, smaller, or the same size as your friends?

6. Is the brake rod in your current booster, bigger, smaller, or the same diameter as the rod in your friends booster? no idea. the current on is a metric 6mm

6. Do you have a drum brake pedal or a disc brake pedal? i have a 69 power disk pedal.

 

[barnett468 418]

21 hours ago, signorc said:

so here's the question of the day.... how can I know which m/c I have? if it's for power disk or power drum....

they look identical but how can I tell the difference?

As far as how much force a master cylinder generates for the same amount of force that is applied to it, there is zero difference between a drum and power brake master.

The difference is that there is a tiny valve (residual) valve as asleanfe mentioned, in the mater or in the line that goes to the drum brakes. On some cars, this valve is in the brake line port on the master, and on others, it is in the line itself, typically mounted on the rear axle on some front disc/rear drum cars.

The smaller the piston bore on the master, the less force it will take to stop the vehicle, but the farther the pedal will travel.

If you have a car with a properly working brake system but it takes a lot of force on the pedal to stop it and the pedal only travels a short distance, like maybe 1". You can install a master sith a slightly smaller bore and it will take less force to stop but the pedal will travel maybe 2" then which is ok as long as it stops abopve the floor by at least 2" for clearance and safey reasons.

The same affect can be achieved by changing the location of the point on the brake pedal that the booster rad connects to. Moving it up a little will be the same as installing a master with a smaller bore, and moving it down will be the opposite.

[barnett468 418]

In your particular situation, I for one think you should try your friends booster if you have clearance for the master, and if your brake lines are long enough, especially since there is a possibility that your current booster may still not provide enough force even when it is working properly, and if that is the case, you will have just wasted a bunch of time and money getting it fixed.

If your brake lines are too short, you will need to get longer ones, but you can buy the brake line in different lengths with the fittings attached, then buy a cheap brake line bending tool.

Do your front calipers have a brake line connecting the two halves so fluid can flow into each half?