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Discussion Starter · #1 · (Edited)
Vacuum brakes.. bad booster?

Ok, finnished up the install of vac brakes, in 95degree weather, getting that pedal out and new one in is far from fun.

Blead all the brakes rp,rd,fp,fd ... it seemed that the passanger side was pushing out hardly any brake fluid when bleeding, and pedal was still very stiff. Driverside it droped all the way to the floor and more fluid came out.

Also before hand I redid rear shoes, drums cut, new springs ect... and new front calipers.

The vacuum line is stright off from billet block, also did not know if a check valve was that right angle attachment on the booster, or if it needs a seperate one attached in the line.

Car now has a very stiff pedal, need two feet just to stop car....

Do you think its a bad master cylinder or brake booster, or something else.

Also I have line locks, and after the install they do not work at all...

No leaks, so many things that could be wrong now... any ideas please help!
 

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You bled the mastercylinder before connecting the lines?

If one rear brake pumped fluid out...then the other must as well......

Might be more air in one side, or the other..but a single line goes back to the rear axle and then splits to each side...therefore it has to go out both sides eventually.
 

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Discussion Starter · #3 ·
Yeah its odd, im not sure, but I did bench bleed the mc before hand.

Im going to buy a new master cyl tommorrow and see if that will fix it, saw it solved some problems with other people.

..if not, im just going to keep throwing money, time and sweat at it and hope it will be fixed! :rolleyes:
 

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Discussion Starter · #4 ·
Well, i bled the brakes by the power of gravity, and then had a friend help me and do it with two people, bled all the sides in order until there was only clean clear fluid coming out, so I know its bled well and cleaned out with no air.

I started the car and hit the brake pedal and I hear air coming from where under the pedal is only when I hit the brake pedal.

Turn the car off and pull out the check valve on the booster and air sucks in. So there was a vacuum in the booster, but every time I hit the brakes I hear air coming from under the dash... bad booster im thinking.

When I try and stop the car it feels like manual braking, very very hard.

Anyway to check too see if the booster is bad? I took the master cylinder off the booster and the pin from the booster that goes to to the master cylinder fell right out, the pin that goes from the back and attaches too the brake pedal is loose and a lot of movement in it, and the area around it looks rotted.

Just asking if I need to go buy a new booster tommorrow, and if so which kinda car do I ask for, is a 85 n/a regal fine? Thanks!
 

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I have a good booster if needed.

I'm willing to bet they want your first born for a new one.

:6:
 

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I had a similar problem, it was the brake booster. About $100 for a rebuilt unit. Also, check under the rear of the brake booster for the thick wire bundle interfering with the shift lever on the column. I broke a shift cable before I realized what was going on.
Dave :)
 

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check out this article on gnttype.org

http://www.gnttype.org/techarea/brakes/Powermaster_to_vacuum.html

The author strongly recommends a new check valve.
Hints:I would highly suggest that you use a new vacuum check valve. My old one passed the tongue test, but it was still no good. Also, I used my hand vacuum tester to check that the 'booster' would hold a vacuum. It should be able to hold what ever vacuum your hand pump will apply. Whether you buy new or used, it would pay to check it out BEFORE installation. It is just too much work to take a chance with a bad part.
He also lists some acceptable donor cars and prices...

Lastly gbodyparts.com says they pull parts for their used vacum conversion kit from 83-87 monte's
 

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Discussion Starter · #8 ·
Thanks for the replys guys! :)
Im just going to buy a rebuilt one I guess More_Boost!!, customs would probally think its a over sized donut and try to eat it if you sent it here. :(

Yeah Huffer that wiring is just in a really bad place, but ill check!

Thanks ahaeragain, I did double check the valve, and it was fine, but if I buy a new booster, should come with a new valve im hoping, if not, ill buy another one.

Do I have to rebleed the brakes again when I reinstall the master cyl?
 

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Nicker said:
Thanks for the replys guys! :)
Im just going to buy a rebuilt one I guess More_Boost!!, customs would probally think its a over sized donut and try to eat it if you sent it here. :(

Yeah Huffer that wiring is just in a really bad place, but ill check!

Thanks ahaeragain, I did double check the valve, and it was fine, but if I buy a new booster, should come with a new valve im hoping, if not, ill buy another one.

Do I have to rebleed the brakes again when I reinstall the master cyl?
You wont have to remove the master cyl, just unbolt it and carfully move it forward enough to remove the booster

:6:
 

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Discussion Starter · #10 ·
Well took the whole thing out already... trying to get a new booster but auto place is having trouble... anyone have a part number for a booster?

All I could find is a sticker with a barcode on it that has the letters FB in bold on it and 53341 written sideways on it, and where the pin goes on a little rubber piece it says 18000228.

I told them a brake booster for a 86 monte carlo, but they did not know single or dual diaphragm.
 

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go to another parts store.
They are all the same. 86 monto carlo, 87 regal V8. If you depresured the booster, then hold the pedal down while starting the car did the pedal fall?? Did the check valve hold the vacuum? My junk yard booster/check valve holds vacuum for weeks. But the master cylinder turned out to be bad.
 

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Discussion Starter · #12 ·
dyermullet said:
My junk yard booster/check valve holds vacuum for weeks. But the master cylinder turned out to be bad.
Ah don't say that!

The whole system is out of the car now, when the car was started the pedal was very hard to push down, and there was little stopping force of the car.

Each time I pushed down on the pedal I heard a loud hiss under the dash, sounding like a vac leak when the pedal was depressed, leading that the booster has to be bad.

After I turned the car off, I pulled out the check valve and air sucked back in, so it held vacuum but still was not working.

I found a part number off gnttype.org of 1800120 but can't find it on gmpartsdirect.com or anywhere else on the net.
 

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just go to another parts place and ask for a booster for an '85 monte, regal, or any other g body car.
 

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dyermullet said:
They are all the same. 86 monto carlo, 87 regal V8.
Yes-yes, listen to the mullet--these will fit, along with many other NA G-bodies. Hard-hard pedal typically related to loss of proper vac. boost. Do you have cruise & is that sw./hose (pedal cancel) OK?
 

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autozone and parts america (both have them). You can even check the website for the part number before you go in (I do). That way when they look it up I know they got me the correct part.

$100 lifetime waranty from autozone. 54-71243

$107 lifetime waranty from advance auto parts (partsamerica.com) 5471243

or go to your local napa, car quest, ect. If someone at the store can't sell you the booster tell them to find someone who knows how to use the parts catalog.

I am happy with the way my car stops after the conversion :) , but I'm not sure about howmuch boost I can hold now for launching at the track. It seems to not hold as much but I havn't been to the track yet to actually test it, and now the radiator is broken and I am broke so it will be awhile untill I test mine.


Sorry about any typos, I am having trouble typeing (stitches in my left index finger). I think i fixed most of them

Scott
 

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Discussion Starter · #16 ·
well thanks :D

I ran over to a junk place, and got another whole master and booster and brake lines and w/e was attched too the brakes for 50$ from a 87 monte. Going to just put the whole system in, looks nice.

This will be round 2, if something goes wrong again, ill be back. :6:
 

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Seein's your on #2, I'm not going to discuss the first booster. That was the problem. Hard pedal means no vacuum assist. You can check the booster before installing simply by hooking up your vacuum line to it. When you start the car, you should be able to push in the plunger by hand, and hear no constant air/vacuum leak. By the way, for any of you guys that are going to change over in the future, the pedal is not hard to change. :D
 

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Nick, you did change the brake pedal, didn't you?

good tip, John! :cheers:
 

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Steve Wood said:
Nick, you did change the brake pedal, didn't you?

good tip, John! :cheers:

if you fail to change the pedal you still have brakes you just have the pedal very close to the floor.
the geometry is a little different....

it really does sound like a ruptured diaphram in the booster.

Good luck
:6: :6: :6:
 

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Red Regal T said:
Seein's your on #2, I'm not going to discuss the first booster. That was the problem. Hard pedal means no vacuum assist. You can check the booster before installing simply by hooking up your vacuum line to it. When you start the car, you should be able to push in the plunger by hand, and hear no constant air/vacuum leak. By the way, for any of you guys that are going to change over in the future, the pedal is not hard to change. :D
I recently did a full conversion for a friend took less than 3 hours start to finish and I changed both front flex lines while we had the system open.

An air Ratchet will save your life when changing the brake pedal. if not at least a ratcheting wrench. this is a 7/16 " bolt so the nut takes a 11/16 and the bolt is 5/8

could be worse you could be chasing powermonster gremlins.... :D
 
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