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Seems to be my month for uncovering new and obscure failure modes...
I was driving the 67 D88 slowly up the farm road today, at about 10 mph. Heard a bang, followed by a new, persistent scraping noise. My gut said it was something in the brakes or a u-joint. Keep in mind that everything in the brakes is brand new. Pulled off the LR wheel to find this:
Remove the drum and it just gets better...
The pretzel is the former e-brake link that runs between the two brake shoes. Naturally, the drum and these brake parts are unobtanium. Anyone parting a 67-70 full size with 11" brakes?
The pin that holds the brake shoe to the backing plate is MIA. I don't know if the retainer came off and allowed the e-brake link to drop out of place or if the link somehow dislodged first. The retainer for the shoe isn't chewed up, so I suspect the former. These retainers didn't really fit that well (and they were Raybestos parts). Once the e-brake link dropped out of place, it was only a matter of time until it lined up with the self adjuster hole in the drum. Yet another reason why I hate brakes that adjust from the drum instead of the backing plate.
If I had to take a guess, I would say that it was the spring that failed first. I always check brake springs with what I call the "drop" method. I drop the spring onto a concrete surface, and if it lands with a dull thud, it is deemed to be good. If it lands with a "boing" or a springing type of sound, then I know it has lost some or all of its temper, and it is bad. The parking brake strut (spreader bar) is going to be the difficult part to find, but the self adjuster parts are still available from RockAuto, as well as a replacement brake drum. The good news is that the 11" drum was used across the GM lineup, so you could probably find a replacement spreader bar and a used drum from any one of the GM cars of the day. I used the RockAuto website to look up the drum, and if you click on the part number, it will give you the "crossover" list.
If I had to take a guess, I would say that it was the spring that failed first.
Don't guess, you'd be wrong. All of the brake springs are brand new and are undamaged by this. Keep in mind that I've driven this car about a mile total since doing the brakes, at a top speed of about 10 MPH.
...but the self adjuster parts are still available from RockAuto, as well as a replacement brake drum.
You don't buy a lot of parts for the 65-70 full size cars, do you?
The self adjuster lever is NOT available anywhere from any source. The CORRECT brake drums are also NOT available anywhere. Kanter sells Chinesium rear drums that are completely different from the originals but will work in a pinch.
The good news is that the 11" drum was used across the GM lineup, so you could probably find a replacement spreader bar and a used drum from any one of the GM cars of the day. I used the RockAuto website to look up the drum, and if you click on the part number, it will give you the "crossover" list.
One more time:
RockAuto is NOT a reliable source for part fitment info. I do have factory parts books. I went through the drum finding problem six months ago. Fortunately, I have an NOS drum on the shelf (thanks, Craig). The other parts are good used only, so hopefully someone has them.
Seems to me I remember installing the hold down springs on my 65, and the retainer did not feel as if it had the same locking tightness to it, if that makes sense. This was with the replacement hardware, I believe from Raybestos. I have used the hardware kits on other stuff and noticed some differences, even the retaining pin being too long. I may have reused the old upper retainer, but can't say for sure.
Seems to me I remember installing the hold down springs on my 65, and the retainer did not feel as if it had the same locking tightness to it, if that makes sense. This was with the replacement hardware, I believe from Raybestos. I have used the hardware kits on other stuff and noticed some differences, even the retaining pin being too long. I may have reused the old upper retainer, but can't say for sure.
Yup, that's exactly what I went through on this car, with the same parts.
I will have to drag out the parts I saved and see what I used. I got the leftovers somewhere. Any difference of a 1/16 in the spring, post length, or the retainer not being pressed right could do this. Even if the die used to press the retainer is wore out, the fit is affected.
I will have to drag out the parts I saved and see what I used. I got the leftovers somewhere. Any difference of a 1/16 in the spring, post length, or the retainer not being pressed right could do this. Even if the die used to press the retainer is wore out, the fit is affected.
I can confirm that the new retainer isn't formed as nicely as the old one. It's much easier to "cam" the pin out of the groove in the new retainer.
Exactly, like the detent in the retainer is not deep or "sharp" enough. I think I matched up the pins and spring length and they were the same. But it has been a few years, can't say for sure. Hard enough for me to remember how to work with drum brakes, another lost art these days. Any of that replacement stuff needs checked closely.
Back in the days regular replacement of the hardware didn't happen, but when hardware is 40-50 years old it is a good idea.
Exactly, like the detent in the retainer is not deep or "sharp" enough.
That is exactly the problem. When I compare the old retainers and the new ones, the detent is not formed as well. Of course, the rust on the old one helps hold the pin in place too.
Joe, if you don't find something on your side of the country I've got the 12 bolt rear end under my 1970 Delta 88 parts car. I measured the drum and its the 11", here's the brakes underneath it. Shoes are mighty thin, but the rest looks usable
At the risk of coming across as a thread highjack, I've got something else you may or may not be interested in. I've got a limited slip carrier that will fit these rear ends, 2.56 ring gear on it. I pulled it from a 1968 full size car many years ago and offered it up here with no takers. Then promptly buried it in the clutter of the garage. Now that I'm retired and have a lot more free time I'm trying to get my Oldsmobile treasure organized. I put this on ebay to get more coverage, but if you wanted it I'd pull it from there and give you the Classicoldsmobile discount. Just let me know. John
We are parting out a 68 Delmont 88 convertible here in Indy. It might be a few days before I could check for the needed brake parts but I certainly will.
We are parting out a 68 Delmont 88 convertible here in Indy. It might be a few days before I could check for the needed brake parts but I certainly will.
Joe, if you don't find something on your side of the country I've got the 12 bolt rear end under my 1970 Delta 88 parts car. I measured the drum and its the 11", here's the brakes underneath it. Shoes are mighty thin, but the rest looks usable
John,
I'm interested in getting spares for all the unobtanium brake parts. I'm more interested in the posi, er... ANTI-spin () differential. Just to confirm, that IS the 9.3" Type O axle, correct? I need to find out what gear sets work with that carrier.
Hey Joe
Glad things did not go worse 4 you and familys sake 2
my old car spat a bearing on the way from mustang island to north
spent 7 nights in edmond ok in the car
wow they have toad drowning storms
I've been really lucky in that respect. Besides this, the rear brake line on my wife's D88 blew out in the driveway, I found the leaking fuel line on my 62 in the storage building, and the fuel pump in my truck went bad parked in front of the house.
I am purchasing the metal dash control ***** & radio from Mark. He has a complete roller 68, 98 he is trying to part out, Tons of unobtanium parts minus engine/trans.
Drum's, knuckles, A arms, rims, diff, chassis parts, dog house. glass etc. Lets help him unload this before it goes to the crusher. Minibike Mark
I am purchasing the metal dash control ***** & radio from Mark. He has a complete roller 68, 98 he is trying to part out, Tons of unobtanium parts minus engine/trans.
Drum's, knuckles, A arms, rims, diff, chassis parts, dog house. glass etc. Lets help him unload this before it goes to the crusher. Minibike Mark
Another place he could list parts is on facebook. There's a group for 88 and 98's and I've sold a few items there. Your right though, a lot of these parts only exist used and a lot of these big heavy cars already went to the crusher.
April 2nd, 2017, 12:26 PM
) differential. Just to confirm, that IS the 9.3" Type O axle, correct? I need to find out what gear sets work with that carrier.
rinse as directed
