Dmity Kiev

i have to low vacuum on idle for brake booster . is there 100% trick to solve this problem ? have C5 brakes on front and on lor rpms car wont stop . when engine stoped pedal is like a rock , no leaks or air , system bleeded twice with pressure

vacuum canister ? - someone tels that it helps but more guys tell that not help

bigger booster ? - i think there problem with space for install it

dual diaphragm ? - is there stock BB single or dual ?

hydroboost ? - expencive . how there a brake with it ?

skirkland1980

iTrader: (2)

i went to manual brakes on mine. if properly done it will work as good as power brakes.

Dmity Kiev

where I can read about manual brake ? how hard is instalation and cost of parts ?

skirkland1980

iTrader: (2)

here is what you need to do. remove the padal assembly and booster and master cylinder (mc). disassemble the booster and remove the rod that goes into the booster. then drill a new hole in the pedal a few inches up from where the rod attaches to the pedal. install a 10mm x50mm bolt and weld it into place. the higher the rod is on the pedal the better the brakes will work. take to rod you removed and cut it to the proper length. you'll need to mock it up to get the length right, then round the end of the rod. you'll need the reservoir from an early 90s truck or maybe an LS1 mc. you need to reroute the brake lines to reach the new location of the mc.

aremy10

iTrader: (3)

is the check valve on the booster bad? when you shut the car off, if you pull the check valve out, there should be pressure comin out of the booster.

Dmity Kiev

at this time i have MC from 4gen car , is it good for manual brake , also in this thread https://www.thirdgen.org/forums/orga...al-brakes.html AlkyIROC says that "The pushrod simply relocated up 1" on the pedal to push straight and also to give a mechanical advantage required for manual brakes." place pushrod up to 2.5cm from OE locaton ?

aremy10

iTrader: (3)

are manual brakes worth converting to? are they better, if so i may do this too

skirkland1980

iTrader: (2)

i only recommend converting for racing or for big cams which are really for racing anyway. if you have good vacuum power brakes are great.

skirkland1980

iTrader: (2)

see, the booster bolts to the firewall with 4 studs, the mc bolts up with 2 studs. when you raise the rod you will use the upper holes to mount the mc, it works out really nice.

Dmity Kiev

my car is daily driving is this good mod for dd car ? i have around 80 Kpa at idle (why so i dont know cam is only LT4 hotcam)
also front brake are C5 12.75 . rear is former front stock caliper. no handbrake

Blind Driver

Have you considered a vacuum pump?

Dmity Kiev

yes i thinkin about it but , what about reliability ? i think it too scare for me for brakes depending in electric . some one use them ?

Blind Driver

I had a '73 Torino, '73 Duster, '85 RX7, and a old Pinto all with manual brakes. Heck, Dad had a '69 dodge 200 with MBs. When I bought a PB equipped car, I didn't really notice a difference.

I would just convert.

rjmcgee

224/230cam


Is that the cam your running? If so some tuning might be all you need. That should have plenty of vacume in a 350.

anthony714

iTrader: (5)

yes agreed,make sure your induction is right and not costing you some vacuum.....if its still low you go t3 options-hydroboost,best but most expensive, electric pump-200 bucks,effective but yes,theres issue.is it reliable,not sure but it does depend on an electric motor,a relay ,and a switch..alot of "ifs"...then theres manual brakes,cheapest but youll have manual brakes,never as good as any type of assisted brakes. fyi forget vacuum canisters. if your vacuum too low all youll do is have more vacuum which is too low to be of use. think of it as a condom with a hole in it,ineffective,so does it matter if you have 2 condoms with holes?

Dmity Kiev

if manual brake is used , what size of front and rear lines should be ?

drperformance

iTrader: (5)

That cam is nowhere close to be needing manual brakes in my oppinion.

fireturd350

iTrader: (8)

I'd say it's time to check the tune again. Since you already have C5 front brakes I wouldn't want to go manuals if at all possible.

I'm using a 383 with a 280/286 advertised duration and lifts of close to .600 or over on 2.08" valves. I'm still using my OEM power brakes.

I tuned the carb with a vac gauge until I got 14+ inches at idle and I also had a vac canister laying around that I threw on too.