Buick Grand National

1987 Buick Grand National Brake System Malfunction When braking Always

My 1987 Grand National does the followig:
If you apply the brakes gradually the car comes to a stop much as normal.
If you apply the breaks quickly the peddle is very hard to push down and no breaking is applied. If you let off slightly the better will depress a bit and then break as normal. This always happens in a panic or quick break scenario. I have been told that it is the master cylander but I wondered if there was a sending unit that triggered the brakes that might be malfunctioning. Can you help.
Thanks
Jim

Jim,
If you have anti-lock brakes, you could try removing the ABS fuse and see if that makes a difference. If no difference, the ABS is OK. The brake booster is another possible cause of your symptoms. Make sure it is getting sufficient vacuum. Make sure it is holding vacuum. With the engine off, make sure it will give several good pumps before the pedal gets hard.
Dale

Dale

The 87 GN uses an electric pump for boosting. I replaced the pump two years ago and if I remove the fuse there are no brakes (That's how I knew the pump needed replacing). It seems like the pump won't kick on fast enough to assist in the braking for a second that's why I thought it might be the control unit on top.

Jim

Jim,
If you turn the key off and pump the brakes several times, does the stiffness change, or stay the same. If it stay hard all the time, you likely have a bad accumulator. This is the little tank/bulb thing on the ABS unit. It holds a charge of brake fluid in reserve and that gives a kick when the power is off, and should help with panic stops as well.
Dale

1987 Buick Grand National Chassis / Suspension & Steering   

my car has a cast iron brake proportioning valve that was supposed to be replaced by a brass valve.the gm part # for the new brass valve is 25509419,which unfortunately has been discontinued.there was a recall for this,but my car was never updated.this valve is located on the frame on the drivers side under the door.i need help locating this brass valve.

Hello, Where have you shopped for the valve? Try NAPA and see if they have it. The AC Delco part # is [redacted] and it just might be there.

Have you contacted a Buick Service Zone Representative and asked for help? A Recall is a safety issue and Buick should be interested even after all these years gone by.

Roger

buick says part has been discontinued and is no longer available.tried all local part stores including napa,with no luck,but did not have ac delco part #.will try again now that i have this part #.thanks for the help.walt

When I suggested talking to a Buick Service Zone Representative I meant talking to your Buick Zone Office for help. Did they turn down helping you?

Here are three phone numbers to GM Dealers that show to have it on the shelf. Call them, ask for the Parts Department and ask for the original GM Part #[redacted] .

Make your own arrangements for purchase and shipping with them.

[redacted]

[redacted]

[redacted]

Roger

hi roger,tried all three phone #'s and nobody has the valve.ac delco # you sent reverts back to origonal gm # and it has been discontinued.local buick zone office says there is nothing they can do.thanhs for your efforts.walt

I refuse to give up!

Try:
[redacted]

[redacted]

)[redacted]

Roger

eureka roger!!!dealer in ca had ONE left on his shelf.now he has NONE.shipping it to me today via ups.thanks ever so much for your persistence!!you've been tremendous!!!once again thanks.Walt

You are welcome! Please click on OK to finish up and that will close the question.

I thank you,

Roger

Hey Walt,

I need you to click on OK to finish up to close the question please....
Thanks,

Roger

1987 Buick Grand National Interior Components   

I need the covers for the attaching screws for the grab handle strap on the door panels.Std g/n grey door panels.need a total of 4 covers.

I think I have 4 brand new covers for you. Is this the rectangular filler for the grab handle colored silver/grey?
Figure $10 + free postage for the set.
[redacted] I accept Paypal.

1987 Buick Grand National Engine   

my grand national has 167k on it on the way home the engine light came on and service engine light was on but thats when the car started shaking all over and vibrating alot and when i pushed the gas pedal to accelerate it would not get the power it was supposed to it would not go past 60 and on the bottom of the car just near the left wheel gas is leaking im thinking that it's the fuel line and can you recomend good parts for the front of my gn i need bearings controll arms the hwhole front thankyou

It sounds like the fuel leak you found is robbing you of adequate fuel pressure/supply (and of course peformance.) With the risk of fire don't take any chances on the fuel lines. Replace all that are bad.

Dealer (OEM) parts are the best but you'll pay a lot for quality. You may be able to save, if parts are currently available, at gmpartsdirect.com

Shop around for OE equipment makers in the aftermarket. These will cost more but offer greater quality. Installation is important too, use a torque wrench whenever torque specs are given (make sure the threads are clean as to not skew the results.)

thankyou very much very helpfull it's my first car and i dont want to let it go thankyou

How long have you had the car?

Any rust? These cars should continue to gain popularity with collectors.

i only had it for one year theres just a little bit of rust on the bottom of the door just a little minor thing but the back seat passenger seat has rust but it's patchable i only paid 6000 for it and i got 4 racing chips and a brand new turbo in it's package and untouched also some cams headers and injectors ive already been offered way more but it's a little project that it will take a while but it will be worth it

1987 Buick Grand National Chassis / Suspension & Steering   

Whenever i step on the brakes the brake light on dash iluminates momentarilly.the brake proportioning valve on top of master cylinder has been replaced.Sometimes brake pedal is very hard and car does not want to stop.

The hard brakes may be be a problem with the vacuum brake booster, but it sounds like the master cylinder probably needs replacing.

Is the master cylinder original? Brake fluid original?

How many miles on the car?

30k mi on car.I am 3rd owner,so don't know if fluid origonal or not,but you've given me a direction to try.If these don't cure problem I'll be back.thnx

1985 Buick Grand National Ignition System   

my gn will not start im not getting fire to the spark plugs and i swapped out coil packs, ignition control module, and crank sensor but still nothing. before it quit running it would not rev to higher rpms and backfired. PLEASE HELP IM GETTING REALLY FRUSTRATED

Hi, please tell me more about the engine. Is it turbocharged? HEI Ignition? Port fuel Injection? 3.8L?

The above information will help me choose the correct troubleshooting chart that I can scan and send to you by email.

May I have your email address please?

Roger

1984 Buick Grand National All Part Groups   

car putting out white smoke when in drive and reverse and not in park

Hello, White smoke is typically a sign of anti freeze burning..If it is white,you will want to have a hydrocarbon test done on your cooling system to check for exhaust gases in your system,possible head gaskets or intake manifold leak.
If its more on blueish side, that would be oil..you would want to have a cylinder compression test done, to check the rings.

1984 Buick Grand National Chassis / Suspension & Steering   

I just purchased a 84 Grand Nation with 88 thousand miles on it. It pretty clean body and interior. It leaks fluid from the mastercylinder or behind it is not a vacuum chamber it is a juction box where the power steering line connect. The fluid appears to be clear it is either power steering fluid or brake fluid. I checked the master cylinder and it was 3/4 empty. But the leak looks like it has been going on for a long time. The old owner told me it was power steering fluid? Why is it coming from the fire wall area?

Hello,

Is the brake master cylinder 3/4 empty?

Yes it was 3/4 empty but the brakes worked fine. I took of the cover to the master cylinder and cleaned out the old fluid it was nasty. I cleaned up all the corrosion around aroung the cover area and refilled the chambers with new fluid. I plan to blead out the system soon. The old owner had a extra quart of power steering fluid under the hood and he would periodically add more as it leaked out.
What is that unit behind the master cylinder?
Is it to assist in breaking?
The power steering pump lines hook up to it I beleive that is what is leaking?