Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
I have 73 discs on my hardtop. I need to replace the pads. My understanding is that the calipers and pads are the same from 69-73, just the rotors and spindles changed in late-72.
The guy at the parts counter looked on the computer and it said that 73 uses pads Wagner #39 (which is what I thought as well). He said he didn't trust the computer and pulled out his dog-eared Wagner book from behind the counter. According to the book, 69 to early 72 uses Wagner #39 pads, and late-72 through 73 uses Wagner #85 pads. He also confirmed that 74 and up uses another different pad, so the book isn't mistaken in that regard.
Anybody know what is the difference? I've searched online but can't find any specs.
He is getting in a set of #85 for tomorrow afternoon. If I have time tonight, I'll pull the pads from one of my calipers and take them to check that they are the same.
Joined: Wed Aug 11 2010, 10:15AM
Location: E WA
Posts: 1230
Mike66Chryslers wrote ... I have 73 discs on my hardtop. I need to replace the pads. My understanding is that the calipers and pads are the same from 69-73, just the rotors and spindles changed in late-72.
The guy at the parts counter looked on the computer and it said that 73 uses pads Wagner #39 (which is what I thought as well). He said he didn't trust the computer and pulled out his dog-eared Wagner book from behind the counter. According to the book, 69 to early 72 uses Wagner #39 pads, and late-72 through 73 uses Wagner #85 pads. He also confirmed that 74 and up uses another different pad, so the book isn't mistaken in that regard.
Anybody know what is the difference? I've searched online but can't find any specs.
He is getting in a set of #85 for tomorrow afternoon. If I have time tonight, I'll pull the pads from one of my calipers and take them to check that they are the same.
Rockauto lists Ceramic D39 pads for $18.89. I have a set but have not installed them yet.
BENDIX Part # D39 CQ CERAMIC BRAKE PAD; Length=6-1/16; Plate=.195; Riveted Front
These also show a 2000 Mercedes application for this pad but not other D39 pads. Not sure if that is real or not
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
@Krautmaster: Thanks for the heads-up. That's what I needed to know.
I got the pads on Friday. They were even able to find me some regular "organic" pads, not the newer semi-metallic kind. I prefer the organics if I can get them because, although they wear out faster, they reduce wear to the discs. IMO, the pads are supposed to be the sacrificial part of the brake system, not the discs.
Anyhow, I installed them this afternoon. What a PITA! I have never had so much trouble changing brake pads!
When I pulled the old pads out of one side, I checked that the backing plates were identical, ie: either pad could be used as the inner or outer pad. Yep, no worries, so I grabbed two pads out of the box and threw them on. I always apply some silicone rubber cement on the back of the pads where they contact the caliper or piston as an anti-squeal measure. This will become significant in a moment, because it added considerably to the job time....
After putting the first side back together and wheel on the ground, I got to the other side and discovered my first problem: The pad that I put on the inside will not slide into the caliper bracket. The pad had been manufactured incorrectly, so that the lining extended past the edge of the backing on one side, causing it to hang-up. I put on my dust mask and ground off the edge of the lining on my bench grinder. Now I had to clean off the silicone and spray the pad with brake parts cleaner and start again.
Putting the caliper on, I discovered my second problem: I couldn't get the outer pad to sit properly in the caliper so that the slider pins would line-up. I pulled the caliper back off the bracket and tried to fit the pad in place. For some reason, these replacement pads had been designed slightly differently than the ones that I took off. The backing plates of two pads had a different shape, so that they could ONLY be used as inner pads! Of course, I had used BOTH of the "outer" pads on the other wheel.
So now I had to jack both wheels off the ground at the same time and disassemble the other side that I had just finished assembling to swap-out the inner pad. The silicone had started to cure by now, so I had to scrape it off and apply fresh silicone.
I was working on this, and had already applied silicone to the backing plate of the replacement inner pad, went to drop it into the caliper bracket, and the lining was also manufactured incorrectly like the other side! Clean off the silicone, then back to the grinder, then spray more brake cleaner, then start again.
On top of all this, I had to use different size sockets for each side of the car. The wheel nuts on one of my front wheels have a different size hex than the other side. One side are original, and the other were from the parts store. When I swapped on the 73 discs, they came with RH studs installed, so I needed another set of RH nuts. On top of this, my caliper slider pins have different size hexes on the ends. One set has 7/16" and the other side are 1/2". I replaced them at the same time, but one set came from one manufacturer and the other set from a different manufacturer.
I also had my 3 year-old son helping me in the garage, til he decided he had had enough and went in the house. I was relieved because my patience was getting pretty thin by this time, even though it was no fault of his, and I was trying very hard not to snap at him (or use foul language).
There, I'm done venting. I feel better now. !stars
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
Krautmaster, the pads didn't hang out the bottom, they hung out one end, and it was the inners. If it was the outer pads it probably would not have mattered.
Justin, the wheel studs are std. size, just that they are all RH thread. The original drums had LH studs on the drivers side, so I had to buy some new RH nuts for that side when I converted to discs. The parts store wheel nuts have a larger hex, ie:require a larger socket. The easiest thing to do would have been to buy new nuts for ALL the wheels, not just one. (Of course I still have LH studs on the DS rear wheel, so I'd still have one oddball.)
The pads in my pic are the most expensive Raybestos ones I could find- I like Raybestos stuff 'cause they make 'em stupid proof, which I need badly at times...