Extremely wierd Problem

§ephiroth · Posted: Tue Jul 15, 2008 7:49 am Post subject: Extremely wierd Problem

My neighbour bought a B13 but when he puts on the A/C the brakes don't hold as well....I drove the car and it does feel like Brake fade goin over Maracas when u drivin too hard....Anyway he went to the mechanic the booster was upside down....they handled that the brakes holds a little better.....but it still gives that same problem now an then with the A/C like 6 out of 10 times he gets it...........Anyone has a clue what the problem could be?

Thanks for the help

centralized(m) · Posted: Tue Jul 15, 2008 8:16 am Post subject:

"goin over Maracas when u drivin too hard..........."

booge · Posted: Tue Jul 15, 2008 8:19 am Post subject:

Somebody call in the X-files....

biggy82 · Posted: Tue Jul 15, 2008 8:56 am Post subject:

does the B13 have good performance without the A/C on? not braking performance eh, acceleration, constant speed etc?

awesomeandre · Posted: Tue Jul 15, 2008 11:18 am Post subject:

had a similar problem when my car was carbie

when the ac in my car cycles the brake pedal used to somewhat get a lil more higher

from what i understood carbie a/c system uses vacuum for the step up and so does the brake booster

have a fuel injected system now and d problem is no more.

but nah i never got brake fade

centralized(m) · Posted: Tue Jul 15, 2008 11:51 am Post subject:

awesomeandre,........lol........i was gonna say that u said but wasnt sure if i correct as i new to the car ting but§ephiroth, he is rite!!!! i have the problem but is not bad and well i know how to work ith it

dmitc · Posted: Tue Jul 15, 2008 12:01 pm Post subject:

i'm not sure bout yuh neighbour b13 but alot of car, mines included has a vacuum line connecting de brake booster to de intake manifold. make sure that line is connected if it suppose to have it and make sure there is no leaks.

§ephiroth · Posted: Tue Jul 15, 2008 6:44 pm Post subject:

Ok thanks alot for the info guys i will pass it on and look into this and get back to you all with results

b18b_turbo · Posted: Tue Jul 15, 2008 7:08 pm Post subject:

weirdist thing i ever heard!

blackNshine · Posted: Tue Jul 15, 2008 8:36 pm Post subject:

^^^ without a doubt

THE SYNDICATE · Posted: Wed Jul 16, 2008 6:32 am Post subject:

John_Doe · Posted: Wed Jul 16, 2008 6:34 pm Post subject:

U see fokes... eh-hem*clears throat*...Its elementry,
" The perpendicular angle of the vortex when used in conjunction with a mid-ordinate zytron, will allways equall to 6 "
therfore, resulting in 'brake fade' ....

sMASH · Posted: Thu Jul 17, 2008 7:34 pm Post subject:

awsomeandre may be right, cause i notice a slight ting with my car, as you mention it
i doh really drive with a/c but when it on i fine i does have to mash ah small ting harder

Hook · Posted: Thu Jul 17, 2008 7:54 pm Post subject:

*sigh*

1. the brake booster is assisted by manifold vacuum
2. the "step-up" unit that works with the a/c leaks manifold vacuum to TB to raise the idle speed a couple hundred rpm to accomodate compressor load on the engine

so u have two devices using manifold vacuum, one is always in use(booster), but when the other one is on(a/c), the first one(booster) fails...see the a/c step-up unit for a solution

the key culprit of difficult braking with the a/c in operation is usually faulty vacuum lines by way of the step-up (provided all other vacuum connections are good)...inspect and replace vacuum hoses as necessary and if the step-up module is adjustable, adjust it so that the idle speed with a/c on is anywhere between 800~900rpm and ensure that you have good brake pedal feel

what may also be possible is that all the vacuum lines may have minute cracks and faults in them, owing to age more likely (cuz nobody really changes vacuum lines too often)
and all these little leaks add up, so it's possible that the brake booster may not be getting proper manifold vacuum assistance in the first place, and then the inclusion of the step-up unit may just be pushing the problem to the point where the booster fails temporarily for the period that the a/c is on

the solution is to change ALL the vacuum lines in the engine bay...just gauge all the different sizes and buy the necessary diameters and their corresponding lengths...then when u ready to change them, offer them up piece-by-piece and change the lines one at a time (better than yanking them all out in a jumble and then trying to figure out which new line goes where)

hope this helps

SNIPER 3000 · Posted: Thu Jul 17, 2008 8:00 pm Post subject:

Great info. hook

THE SYNDICATE · Posted: Fri Jul 18, 2008 6:27 am Post subject:

TriniGT · Posted: Fri Jul 18, 2008 7:23 am Post subject:

Nail on the head Hook.

*KRONIK* · Posted: Sat Jul 19, 2008 6:20 pm Post subject:

good read here...

ryanm · Posted: Sun Jul 20, 2008 8:38 am Post subject:

one other thing to check is the checkvalve on the brake vacuum line. The brake pedal should be soft the first two or three pumps first thing in the morning. It it starts off stiff then check it.