[Dale Ross]

I think I saw a thread on this a year ago, but at that time I didn't have the problem so I didn't read it closely. SOMETIMES, not always, my '71 GT will let out a big shuddering bang when I apply the brakes. I've removed both rear drums and examined both rear brake assemblies and don't see anything amiss. Has anyone run into this and what's the fix? Thanks!

 

[opelgtmaster3]

my gt is doing the same thing. i dont know what it is but my is making the noise in the front

 

[rustbucket]

my gt is doing the same thing. i dont know what it is but my is making the noise in the front

I had a 65 cadillac calais, it made a loud noise in the brakes and it turned out to be a cracked brake shoe, it was almost undetectable for it was a very fine hairline. I don't know what the noise would be on a set of calipers.

Rustbucket

 

[pvcar]

well i had that same thing happen on my gt it was due tome just being stupid, well i decided one day i would remove my antena when i was gonna get it painted well i started to remove it and got it out of the hole were it was held in at and then it was just hanging down in the wheel well at that time i had to go do something and then didnt finish removing the antena i didnt get to work on my gt for a few days after that so i had forgoten that i still needed to remove the antena the whole way, well it was just hanging there and when i took it out to test drive it around the street i sped up and then hit the breaks really lightly and i heard a loud banging noise that i had forgetten to tighten something on the drive train well i couldnt figure out what the heck the noise was but it turned out to be the antena when i stoped it would get stuck between the tire and the body panel which caused the loud noise, cut that damn antena off test drove it and havent heard the noise since.

 

[Gumby]

I'm having this issue with my GT. During the first few times I brake after I start driving the rear brakes will make a loud bang noise and the rear wheels lock up for a second. This goes away after a few brakes but it is rather startling at first. It sort of feels like the rear brakes are going from zero to 150% because it doesn't happen until I depress the brakes past a certain point...

Does anyone have any idea what causes this issue? I'd like to get an idea of what I am getting into before I pull this thing apart.

 

[opelwasp]

Sounds like break fluid on the shoes. It happened to my dads GT last year. It got so bad the rear wheels would lock up altogether when you pressed the breaks. Had to replace the rear wheel cylinders and shoes.

 

[bear]

I had the same thing happen on Willit? At first I thought it was the disconnected lower spring l found when pulled the drum off. It turned out to be brake fluid saturated linings. I first wire wheeled the new linings to remove the glaze on the linings, that didn't help, so I trashed them and new linings are again on the car. HTH.

 

[blancojp (R.I.P.)]

I have seen this problem many times on different cars and it is always something simple or overlooked. You will need to take your time and go over the area where the noise is comming from.

 

[Bill Hoffmann]

I think you have brake fluid on the rear shoes. It will make them grab. You want to make sure you eliminate the leak first, clean and dry the drums very well with brake cleaner, and install new brake shoes. The most likely cause is leaking wheel cylinders, but I would also be on the look out for gear oil going past the axle seal.

Also make sure they are adjusted properly.

As far as wheel cylinders are concerned, I'm treating it as routine maintenance to take them apart, clean and reassemble them periodically. They seem to get contaminated more quickly than the other parts of the brake system.

Bill

 

[Rionart]

I've had grabbing rear brakes on 2 of my Opels recently:
On the 72 Ascona it was brake fluid on the linings...new wheel cylinders and new linings fixed that one.
On the 80 Ascona it was a broken lower shoe spring...again, replaced and fine.
HTH, Rob.

 

[Gumby]

Ok assuming that is it, why does it stop doing it after a short while of using the car? Also (again assuming this is the issue) are these parts that I can just go pick up from NAPA, autoZone, etc or do they need to be ordered from someplace like OGTS?

 

[jvandyke]

I'm having this issue with my GT. During the first few times I brake after I start driving the rear brakes will make a loud bang noise and the rear wheels lock up for a second. This goes away after a few brakes but it is rather startling at first. It sort of feels like the rear brakes are going from zero to 150% because it doesn't happen until I depress the brakes past a certain point...

Does anyone have any idea what causes this issue? I'd like to get an idea of what I am getting into before I pull this thing apart.

Sounds just like what my old Sunbird would do. I was told it was the rear drums, they were thining out, the shoes would travel quite a ways on the initial application of the brakes and "grab" when they caught, only did the first time or two each day, then they must have self adjusted or whatever and they were good for the rest of day. Car would squat down quick, pretty funny. I never fixed it, just sold the old heap. Time for new drums? been turned, worn, once too often?

 

[madhatterpdc]

A loose or missing caliper bolt will make a horrendous racket.

 

[Gumby]

Sounds just like what my old Sunbird would do. I was told it was the rear drums, they were thining out, the shoes would travel quite a ways on the initial application of the brakes and "grab" when they caught, only did the first time or two each day, then they must have self adjusted or whatever and they were good for the rest of day. Car would squat down quick, pretty funny. I never fixed it, just sold the old heap.

That sounds like what is happening to me. I'll have to look into it this weekend.

A loose or missing caliper bolt will make a horrendous racket.

I'd imagine it would, but wouldn't that be a little different that a loud bang noise?

 

[madhatterpdc]

Perhaps I should have been more specific. A missing caliper bolt will indeed make an enormous bang when the brakes are applied. This is the outward effect of the caliper pivoting on the remaining bolt and being slammed inward into the hub section of the rotor or swinging outward and knocking on whatever limiting factor it runs into first. Long term effects of this scenario include damaging the pads, scoring the rotors, or most likely damaging the caliper slides. Other effects can include severe damage to body work, bumpers, glass and loved ones as the result of acute loss of control and immediate impact. When in doubt, please have a trained professional physically inspect all four corners

Regardless, if the bolt is missing you will need to replace ASAP. And you MUST use a grade 8 bolt. No stainless or cheap stuff from Home Chepot. It's been a while, but I *think* the bolt is a 10mmx1.25 pitch, which I remember being a non-standard pitch for that size bolt. Best to bring a bolt with you and match it up.

Also, Rob's comments on brake fluid on the linings from leaking wheel cylinder and broken spring are salient and worth investigating.

 

[Gumby]

I tested a theory I had. If I pump up the brakes before applying the brakes then it doesn't go bang and lock up. Either way I'll take care of it ASAP. The car wasn't really used much since 02 until I got it. So some things are bound to go south.

I'll ask again since no one answered it, but for the brakes can I get the pads, rotors, liners, etc from a local autoparts store or will I need to get them from an Opel specific parts dealer?

 

[yellaopelgt]

I got most of the parts on-line, do a search and find the best prices. Locally,the prices were nearly double! Sorry, but I honestly cant remember where I got the stuff from.........autoparts.com rings a bell tho. Just a lil hint....you might want to replace the brake hoses while you're at this. They seem to deteriorate quite often and collapse internally. Which causes some pretty strange things to happen.JMTCW
Joe

 

[Gumby]

The brakes and clutch were re-done less than 10,000 miles ago... but that was 10 years ago. Anyway when I take them apart I'll probably end up replacing a bunch of stuff just for my own peace of mind.

 

[madhatterpdc]

Please don't forget our friends at Opel GT Source, yes you pay a premium on price, but the parts will always fit and those guys are great to deal with.

 

[Gumby]

I just ordered a head gasket from them.