What have you done to your square lately??

[Goldie Driver]

Well, chasing a brake issue- specifically on wet roads with a relatively moderate pedal pressure the fronts will lock.

Not comforting for sure.

Did some research last night, and one suggestion was to check the rears to he sure they are pulling their load.

Plan was to clean the shoes and drums, rough them up with a wire wheel on the drill ( which may be plastic- its not what you are probably visualizing) and adjust them.

Did all that, plus one primary shoe - WTF ?

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Gotta get back in the PS side and double check the bottom shoe return spring and probably clean and lube the adjuster again.

No slot in the backing plate , so gotta pull the drum to adjust things and I may have the PS looser than the DS.

Don't understand why these damn things are fighting me so hard - I have done drums plenty of times before, and that cracked shoe was from a shoe replacement as well as new drums at the same time.

 

[Vbb199]

I have a theme going if you can't tell lmao. Resto - rat , rusto - mod........one of those .

Whatever your theme, i like it.

 

[Grit dog]

^Never seen a cracked brake shoe lining. Strange. How old?
How many miles?

 

[Vbb199]

26-27 kPa is pretty good vacuum, especially considering you aren’t running a stock cam. Usually even mild performance cams idle over 40 kPa...

Doesn’t seem like a vacuum unless there’s something else you’re seeing in addition to that.

Im seeing 22.5" in/hg at the front port of the tbi with a gauge, but 8" in/hg (27 kPa) from the map. I just replaced that also.
I know theres some variance in it related to sea level, but im not that far above or below it. I think like... 790 ft?

Im about 99% sure the vacuum line that taps off the back of the tbi for the map probably has damage. A pinhole, crack, something.
Or the map just isnt grounded correctly, while the trans was out i was able to stick my head in the tunnel and inspect the harness at the back of the motor, didnt see anything out of place or broken. So im to assume i just have a bad vacuum line for the map.

 

[Brett77]

Finished up with Sniper install and my truck and it is working great so far.

 

[Octane]

I like my... toys... like i like my trucks...full size.

But i did just get a little squirt gun i can fit in my pocket[/QUOTE....Biden may not be happy with hi capacity squirt guns either! Lol

 

[Frankenchevy]

Im seeing 22.5" in/hg at the front port of the tbi with a gauge, but 8" in/hg (27 kPa) from the map. I just replaced that also.
I know theres some variance in it related to sea level, but im not that far above or below it. I think like... 790 ft?

Im about 99% sure the vacuum line that taps off the back of the tbi for the map probably has damage. A pinhole, crack, something.
Or the map just isnt grounded correctly, while the trans was out i was able to stick my head in the tunnel and inspect the harness at the back of the motor, didnt see anything out of place or broken. So im to assume i just have a bad vacuum line for the map.

For some reason when you use google or some other non automotive specific converters on kPa to inHg it will say 27 kPa is ~8”. That’s not correct. I did a lot of digging when initially tuning my sniper and can’t remember the logic, but here’s a conversion.

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So you’re actually where you want to be.

https://board.moparts.org/ubbthread...736356/holley-sniper-440-timing-question.html

 

[SquareRoot]

The time has come . busy weekend, this weekend. Replacing all my steering and suspension components this weekend and lowering the truck 3frt/4 rear. As well as new rotors/ hubs, wheel bearings and brake pads and completely bleeding the system. Wish me luck

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Damn, I love that patina. That looks awesome!

 

[gmbellew]

@Vb199 - It is gage pressure vs absolute pressure thing. You are measuring vac directly with a gage, but the MAP is giving absolute pressure. 100Kpa is atmospheric pressure. So to convert the MAP reading to vac you need to take 100kpa - MAP kpa and then convert that number to inches mercury.

 

[Vbb199]

For some reason when you use google or some other non automotive specific converters on kPa to inHg it will say 27 kPa is ~8”. That’s not correct. I did a lot of digging when initially tuning my sniper and can’t remember the logic, but here’s a conversion.

You must be registered for see images attach

So you’re actually where you want to be.

https://board.moparts.org/ubbthread...736356/holley-sniper-440-timing-question.html

Wtf? Really???
I thought it to be this equation=
kPa ÷ 3.38 = X
"X" being in/hg

 

[Vbb199]

@Vb199 - It is gage pressure vs absolute pressure thing. You are measuring vac directly with a gage, but the MAP is giving absolute pressure. 100Kpa is atmospheric pressure. So to convert the MAP reading to vac you need to take 100kpa - MAP kpa and then convert that number to inches mercury.

Ok. I responded before i read this.
THANK YOU!
You too @Frankenchevy

So the actual formula is
(100kpa - Map kpa) ÷ 3.38 = in/hg

And with 27 on a sensor, that brings me to 21.59 in/hg, very close to what Frankechevy's chart says
and very close to my gauge readings. So i DONT have a vacuum leak then......hmmm.....

Excellent! Then that puts my mind at ease.

 

[Frankenchevy]

Wtf? Really???
I thought it to be this equation=
kPa ÷ 3.38 = X
"X" being in/hg

Do you notice that it has the lowest kPa reading at idle and it increases with increased throttle?

That’s what the sniper did. It would idle around 26 kPa and at WOT would be around 100 kPa. It had an inverse scale of inHg.

Edit: now I see it’s been clarified by gmbellow

 

[Goldie Driver]

^Never seen a cracked brake shoe lining. Strange. How old?
How many miles?

I will guess- tops 2 years old, and maybe 20K.

A 1st for me, too.

Retarded Auto stuff (Advance) - I kept the newer shoes I changed out for brand new ones to go with the new drums so had a spare handy.

Unexpected.

 

[RedBeard_83]

Finished her up today. Maybe go lower in the future but It looks good for the time being . happy with the results . now just need alignment and to break in ths brakes as they appear to be a little tight on rotor and cause some squeeling while driving. ( gotta fix that sh*t)

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[Camar068]

For some reason when you use google or some other non automotive specific converters on kPa to inHg it will say 27 kPa is ~8”. That’s not correct. I did a lot of digging when initially tuning my sniper and can’t remember the logic, but here’s a conversion.

You must be registered for see images attach

So you’re actually where you want to be.

https://board.moparts.org/ubbthread...736356/holley-sniper-440-timing-question.html

Thanks for stirring the pot a bit, I did the "google" conversion and it didn't sound right at all lol. Thanks all for the correct formula.