1988 5th brake rotor/drum questions

[8v-of-fury]

Hello good people of the FMJ world !

I dont post often, because for the most part my old girl runs along just fine year after year. However, at the end of last season I got stranded for the first time in about 7 years AND the front brakes finally wore out. I don't know that they've ever been replaced.. It was bought new by my grandfather, and he passed in 97. My grandmother drove it until 2012 or so but it spend its life in Scarborough, Ontario. Which meant just a 10 minute drive to everything you'd need.

Anyway. upon looking up brake stuff, It shows differing size brake components. The car is in storage for the winter so I cant just go have a peak at it.
Does anyone know by my fender tag which size rear brakes I have?

 

[Mikes5thAve]

Being a 5th it's pretty much guaranteed to be 10".

 

[Duke5A]

The rear brakes are the only ones that could be either 10" or 11" drums. Mike is right though, a Fifth Avenue with 11" rear brakes would be a unicorn. I don't even know if there was an option to get the 8.25" rear axle and 11" drums from the factory on a 5A.

I know for sure though that the fronts are 10". You couldn't get 11.75" discs on the front from the factory in any configuration. If you wanted to upgrade the fronts to 11.75" though it's an easy swap. Only thing you need are rotors and caliper adapters. All of which can be purchased from Dr. Diff. It'll still fit under 15" wheels as well.

 

[Aspen500]

According to the (79) parts catalog, 10" drum is for all except 45, which is 2 seat wagon.

 

[Mikes5thAve]

Police package cars had 11. I think taxi might have had them too but by 88 those were also 10".

 

[LSM360]

If you're going to buy new drums beware. So much junk right out of the box. I bought a set of Reybestos 11" finned drums for my AHB and they were junk. I would have had to try and have them turned to have any chance of using them and Rockauto wanted me to send them back for a refund. The shipping would have cost me more than I would've gotten in refund. Right into recycle bin and luckily found NOS set on Feebay. That was a few years ago. Maybe some can recommend a brand now or it'll be easier to find a NOS set of the 10" ones. Good luck wading through the sea of absolute crap parts!

 

[Aspen500]

If you're going to buy new drums beware. So much junk right out of the box. I bought a set of Reybestos 11" finned drums for my AHB and they were junk. I would have had to try and have them turned to have any chance of using them and Rockauto wanted me to send them back for a refund. The shipping would have cost me more than I would've gotten in refund. Right into recycle bin and luckily found NOS set on Feebay. That was a few years ago. Maybe some can recommend a brand now or it'll be easier to find a NOS set of the 10" ones. Good luck wading through the sea of absolute crap parts!

I concure with that 100%. Quality of parts from you know where is not good at all.

 

[Mikes5thAve]

Good to know about the drums. If I need them I'll buy local so they're returnable.
I've had problems before with rock auto sending bad parts and the return wasn't worth it so now I only buy stuff from there that has a pretty low chance of having problems.

 

[LSM360]

Good to know about the drums. If I need them I'll buy local so they're returnable.
I've had problems before with rock auto sending bad parts and the return wasn't worth it so now I only buy stuff from there that has a pretty low chance of having problems.

Yes, that was another mistake on my part. If they are available local definitely do it that way so you can march back up to a counter and hand them to an employee and get your money back. I'd also keep my eyes open for NOS ones at decent price even if you don't need them now. The 11" police ones are probably all but gone but the 10" ones may still be out there.

 

[LSM360]

I just checked Feebay for "NOS Mopar brake drum" and the closest thing for an M Body was this, and I don't think it'll fit. It's 10" finned drum for Cordoba. Looks to wide too me like 10x3? and it's only one. I don't have part # in front of me for M bodies but I don't think they cross over for Doba's and M's. This is the first finned 10" drum I've seen. $100 including shipping is a deal IMO, knowing what I know about quality of aftermarket. Interesting.

https://www.ebay.com/itm/314372337485?

 

[Aspen500]

Cordoba also had 2 1/2" wide shoes. The only difference between Doba and F/M/J is the Doba uses finned drums vs non finned for FMJ.

 

[Mikes5thAve]

The 80s M body drums were finned. Only the early ones didn't have them.

 

[Duke5A]

Rear disc swap kits that utilize factory parts are easier and easier sells at this point. My rear axle uses Ford Explorer discs.

 

[LSM360]

The 80s M body drums were finned. Only the early ones didn't have them.

Ahh. I didn't know that. I thought only the police 11" ones were.

 

[Mikes5thAve]

Oddly enough the first time I had to replace drums they gave me 11" ones which of course were wrong and the 10 ones were too tight with new shoes so the old ones went back on. I used those new drums a couple years later on another car.

 

[dermohar]

Hello good people of the FMJ world !

I dont post often, because for the most part my old girl runs along just fine year after year. However, at the end of last season I got stranded for the first time in about 7 years AND the front brakes finally wore out. I don't know that they've ever been replaced.. It was bought new by my grandfather, and he passed in 97. My grandmother drove it until 2012 or so but it spend its life in Scarborough, Ontario. Which meant just a 10 minute drive to everything you'd need.

Anyway. upon looking up brake stuff, It shows differing size brake components. The car is in storage for the winter so I cant just go have a peak at it.
Does anyone know by my fender tag which size rear brakes I have?

View attachment 49082

You can still get the non finned rear drums from Partsource -as you probably know Orillia has one of the franchise stores. Can you get underneath to look at the rear diff casing?
dermohar - Scarborough, ON

 

[8v-of-fury]

Thank-you all for the SUPER informative replies! As it would appear, I may have a fairly shitty time trying to find some rear brakes.. haha.

I am pretty certain it has the 7.25 diff. It also definitely has a finned drum from what I recall the last time I had the wheels off.

 

[Aspen500]

7.25 has a round cover with flats on the flange, 8.25 is basically an oval shape, cover and flange.

Either drum, finned or unfinned will work regardless of the origibal style, if it comes down to that.

I replaced my drums right after buying the car in '87, back when they still said "Made in USA". Same drums that are on the car now. Original 7.25, now 8.75 but the drums are the same no matter what size axle.

 

[Mikes5thAve]

Easier then that, for 7 1/4 the axle tubes get narrower at the center housing, for 8 1/4 they're the same diameter from end to end. Only applies from about 1981-89 cars.

 

[Mr C]

I'm doing the brakes on my 89 5th Ave and used partsavatar.ca and got everything I needed for cheaper than I could locally. It also had free shipping which is pretty unheard of for a Canadian company.

Be careful though... they labelled the front calipers as left and right for the same part number, you need one of each part number.

99% that your 88 has a 7.25 rear end in it.