A few years back I bought and installed OER MN5005B....front disc brake conversion kit with tubular uppers from classic industries. My question is what lowers will work with this kit?. Should I just rebuild my stock lowers or buy qa1 lowers. Also I’m going to stick with torsion bar set up. I’ve got a 318 I’m going to be putting in it with 904 trans and 8 3/4 out of a B body wagon that will need to be cut down to stock width. For the rear I’ll probably stick with drums. Also what proportioning valve and power brake setup should I go with. Im trying for a lower budget build. I don’t need anything super fancy. I just want to make sure I get compatible parts that will function well together.
Classic Industries OER front conversion question
- Thread starter Firedart
- Start date
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So this is your set up correct?
OER MN5005
If that's the case then what you have is just the stock 73+ BBP disks with a set of tubular UCA's. Your stock lower control arms will work just fine with a rebuild, if you're doing that then you can add a boxing plate to the bottom of the stock LCA which you can also use to correct any wear or play that has developed in the LCA. Jim Lusk has a nice video on that...
I actually prefer manual brakes on these cars, with a 15/16" master cylinder you get a very nice brake feel without being too heavy or too overboosted. If you still want to go power, DoctorDiff has a nice Bendix reproduction booster available. It's not the cheapest, but it is a high quality booster that looks correct for the application. Bendix Style Dual Diaphragm Booster for Mopars
He also sells the reproductions of the original combination valve, which should work fine for you since you're running the stock front and rear BBP brakes.
Mopar 1 Piece Proportioning Valve
There are cheaper ways to get it done, but brakes aren't something you want to cheap out on. And since you have mostly factory reproduction parts so far, keeping with factory reproduction parts will mean they should all work well together.
OER MN5005
If that's the case then what you have is just the stock 73+ BBP disks with a set of tubular UCA's. Your stock lower control arms will work just fine with a rebuild, if you're doing that then you can add a boxing plate to the bottom of the stock LCA which you can also use to correct any wear or play that has developed in the LCA. Jim Lusk has a nice video on that...
I actually prefer manual brakes on these cars, with a 15/16" master cylinder you get a very nice brake feel without being too heavy or too overboosted. If you still want to go power, DoctorDiff has a nice Bendix reproduction booster available. It's not the cheapest, but it is a high quality booster that looks correct for the application. Bendix Style Dual Diaphragm Booster for Mopars
He also sells the reproductions of the original combination valve, which should work fine for you since you're running the stock front and rear BBP brakes.
Mopar 1 Piece Proportioning Valve
There are cheaper ways to get it done, but brakes aren't something you want to cheap out on. And since you have mostly factory reproduction parts so far, keeping with factory reproduction parts will mean they should all work well together.
I should have stated in my original post that I have a 70 swinger. The car had original SBP drums front and rear. The other rearend I’m putting in has BBP as well. Do I need to upgrade the master cylinder or will the old one work with the bigger brakes and just change out the prop valve?
It depends on what master cylinder is in there. If it was for 4 wheel drums at the very least you'll have to remove the residual pressure valve from the disk brake side. If the chambers of the master cylinder are the same size I would probably just change it out though. The disk/drum masters have a larger reservoir for the disk front brakes.
I don't hear about many people replacing the LCA. Is there a reason why this doesnt see as much attention? Whats the reason, in the video, for adding the stiffening metal? I'd assume these can bend/twist under heavy torque situations like road racing or is it just a good idea for improved handling? Just curious about lots of Whys???
The LCA's aren't usually replaced for several reasons. The primary reason is that from '67-76 the LCA's were identical if they didn't have sway bar tabs. So if you do a disk brake upgrade you just buy the disk lower ball joints and you can use them with any of the LCA's. With the UCA's there are two versions, small ball joint (67-72) and large ball joint (73+). So if you upgrade to BBP with the later 73+ disks the spindles take the larger upper ball joint, which doesn't fit into the earlier UCA's. There are adaptors to use the small ball joints with the large ball joint spindles, but most people upgrade to the larger ball joint UCA's. The other thing is the LCA's don't have any built in alignment geometry. With the UCA's the factory design has very little caster built in. Aftermarket tubular UCA's have additional caster built in so you can get more modern alignment numbers. So there are two good reasons to change the UCA's, and no real benefit to changing the LCA.
As for boxing the LCA, there's a couple reasons to do that. One is that they're just stamped steel and they have an open side. So adding the plate to the bottom boxes in the LCA and makes it more resistant to twisting and flexing. The other Jim talks about in the video, the LCA's tend to "open up" at the pivot end. If you clamp the ends of the LCA with the pivot together and then weld the boxing plate on it keeps the ends of the LCA from spreading, further limiting flex in the LCA. I think it's a must do for any car being set up for better handling. Keep in mind these cars were intended to run bias ply tires, which had a lot less grip than even just the plain all season radials (BFG T/A's, Cooper Cobras) that most people run. More grip at the tires means more force on the suspension, which means more flex. The more tire you put under the car up front the more you need to reinforce things to prevent excessive flex.
Perfect. Exactly what I was curious about. I'll check the gap on my lca's before continuing with my swap.
I purchased that same summit racing disc brake conversion kit today. I've been looking for nearly a year and recently UCA's have become impossible to purchase short of QA1's for 3 bills. However this set with the uca's looks like a good deal (provided corona doesn't stop them from coming)
I don't think many of the OE style are selling anymore. Even with the offset UCA bushings the positive caster is pretty limited with the OE style UCA's. Unless you're running bias ply's running the tubular UCA's and the additional caster they have built in is a pretty good idea.
Pshas192
Active Member
I am perplexed, my 1972 Duster 340 has manual drum brakes and I want to convert to 11.75 discs following the (disco-tech) system.
I bought the QA1 tubular upper control arms and adjustable strut rods.
I'm keeping the lower control arms. They are refurbed / boxed with Delrin bushings.
Do I need to back up and get big ball joint uppers? Can I continue with the QA1 tubular uppers that I have?
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You need large ball joint upper control arms, or adaptors, if you want to run the 73+ spindles you need for the 11.75’s. If you bought small ball joint QA1’s you need ball joint adapters. Or send them back for exchange. QA1 makes both small and large ball joint uppers, so it depends on what you bought.
Pshas192
Active Member
Thank you. I am now working with Peter Bergman and looking into alternative systems.
famous bob
mopar misfit
HEY BLU , WHAYT ARE THE CHEAPER WAYS U MENTIONED / What is the best set up to run w/ coil over springs , using a stock k-frame .
Am running 4 wheel discs already on the car , want to go back to the stock kframe w/o torsion bars .
The best set up is not to run a stock K-frame with coil overs. One or the other.
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