Hissing sound in the cabin - brake related

SON240sx Automotive
1

ok so i picked another hatch today ('89) with no abs.

The brake peddle is hard as hell and doesnt sink to the floor.

The car will stop but the brake performance is crap. when i press on the brakes, i can hear a hissing sound in the cabin and i can see the idle drops a little bit.

I think it may be the brake booster, but can anyone confirm this? im thinking there is air in the lines and it may need to be bled but how did the air get in the lines in the first place? Im assuming there is a vac leak or something since my idles also drops…

replace the booster or should i just try and bleed the lines first?

Oh, the peddle doesnt get softer or any harder the more i pump the peddle…

I need to get this thing on the road asap, but i dont want to drive it till this is fixed! I have to stop with the hand brake for now ! Thats a bonus though, an old hatch with a working hand brake!

thanks

2

For the hissing, check for snakes under the seats. They like to slither up through holes in the floor.

Seriously though… I would say it is your booster. It is either dead or you have a large vacuum leak and it is not getting any vacuum.

3

Snakes in the car!!!

4

haha ill check for snakes,i dont want them to bite my legs!!

and well ill assume its the booster cause i can hear the hissing in the cabin…if it was the MC, i dont think i can hear it cause its totally connected outside the car , unlike the booster right? I hear to change the booster, you have to do some work from the cabin as well as the engine bay…right? ive never actually changed one, but its what i heard.

also, is this a difficult/annoying job to do? Hours or an hour? scale from 1 to 10, what would you rate this?? Same goes for the MC?

thanks for the input btw!

5

i rate this job as a 2 out of 10. it is super easy.

heres some steps to it.

  1. crawl under your dash and the end of the brake pedal bracket has 4 12mm bolts ( i think it was 12mm i could be wrong)

  2. there is a pin on the little fork you have to take out, a cotter pin also holds the pin in place. ( this part is the same as the clutch master part)

  3. take off the brake master cylinders, which is the 2 12, or 14mm bolts.

  4. disconnect the vacumn line on the booster.

  5. pull out the brake booster.

  6. assembly. reverse of disassembly basically. but make sure you adjust the pedal right, too low would cause your braking to be shitty, and too high will make your brakes lock up after you drive it for a few mins, i know from experience.

adjusting instructions: 14mm nut is behind the fork (acts as a safety, so it doesnt move and stuff) loosen that and you can adjust the pedal with the rod.

this is a very simple thing to do.

and if i left out anything, please add. but i dont think i left anything.

hope this helps you out.

6

nice steps! and it does sounds easy, so maybe ill jsut do that instead of paying someone! lets hope for some + temps tomorrow!

thanks!

7

now before i buy a MC and/or booster, i did mroe reading on old posts and it seems when the booster fails, everyone that has had that problem has a sinking pedle. Mine is just really hard and has very very minimal travel.

Any ideas? maybe the booster and MC are good, but the lines just need to be bled?

8

Perhaps the master cylinder is seizing and causing this kind of pedal feel? Hard to say.

I’d triple-check the vacuum line for a leak/crack as well as cheap insurance that that isn’t your problem.

Good luck.

9

i would have to disagree with got_boost_s13 the hissing sound is probly the girlfriend getting pissed at you for spending to much time in the car and not in her… it happens

10

haha well she’s gone back to london for 8 months, so im free to work on it all i want!

and is the vac line you speak of, the one big one off the boosted in the engine bay?

11

Yup, pretty sure - think it has one of those metal clips holding it…

12

ok awesome, ill check it out in the daylight tomorrow

13

i think you should try this.

also downloading a FSM will help you out alot! just a suggestion :wink:

heres also a diagram of what you need to take out in the cabin.

14

that is friggen awesome dude! thanks so much man! appreciate it a lot !