[Calpantera]

So I finally decided to deal with my dragging rear brake issue on my 67 and came up with a few surprises. First off I pulled the MC cover and noticed the rear reservoir was pretty much empty, so then I assumed I had a leaky wheel cyl on the back. Then as I looked at the line routing I noticed that the rear reservoir routes to the front of the switch block and the front reservoir routes to the back of the block. Is this correct? My assembly manual does not show it this way. Also should both reservoirs be the same size for front disc and rear drum? I know I have seen stock set ups that had both drums and rotors and the reservoir that fed the discs had a larger capacity (not sure what kind of car I saw this on); I assume this was because the calipers had a larger capacity than the wheel cylinders. Now my rear end is out of an early ‘70s nova and I am not sure that the front disks OR the MC are stock either (MC has the number 5462810 casted on the side facing the engine). The brakes are manual.

Any feedback would be great

Bill

[Everett#2390]

My '68 AIM, UPC 5, A1 & A2 shows rear tube from m/cyl to rear port of switch assembly and same for the front, front to front.

Dsic/drum m/cyl's do have a larger reservior for the discs.

[Calpantera]

Ya my AIM for 67 shows the same thing, I thought that the reservoirs were different sizes for disc and drum. Question is what should I be using for an M/C, did '67s even come with a manual disc/drum config? OK answered that question by checking the AIM, J52 is disc brakes but6 I notice that J52B shows a balance valve and the M/C has the part number 5461705 (Manual, J50 power option has different number). Quick search on the web gave me this thread http://www.camaros.net/forums/archiv...p/t-29695.html (Searching the forums did not, thank you Yahoo)

[Calpantera]

So after reading that thread I am pretty sure the manual disc brakes are not stock as Panther states that only 205 cars were built with that option in '67. My car is a plain jane according to my cowl tag

11D Built 4 week of November 1966
D Red interior
67-12437 Camaro with standard interior, coupe
NOR 39730 Norwood, Ohio
741-Z Red Strato Bucket Seats (No headrest)
C-C Exterior paint, Ermine white with Black Stripe

I wish I had the build sheet
Anyway so to match the M/C to the calipers I guess I need to know what size caliper pistons are huh? Anyone know how to ID them? I also assume I will need to add a balance valve? BTW I am not looking to do a resto here I just want working brakes

[Everett#2390]

You might be lucky to find the calipers are '69 and later, a single piston.
Yes, you will need to know the diameter of calipers.
Probably the balance valve will be needed.
I might see if a '69 m/c might work if '69 calipers.

[Calpantera]

Once my back chills out (did something stupid and hurt it) I will pull a wheel and try to ID a caliper. I assume there is a casting number or something. If not I will post some pics to see if the brain trust here at TC will ID them for me (I know you guys will)

[TMessick]

When you pull a wheel, it'd be good to measure/count:
-- Rotor outside diameter (should be ~11")
-- Rotor thickness (should be ~1")
-- Number of caliper pistons ("stock" 67/68 is 4/caliper 2 on each side of the rotor, 69+ is one piston)
-- Caliper piston diameter (67/68 is 1+7/8", 69" is 2+15/16")

For a 69+ type system with the single piston calipers, I'd just run a stock replacement '69 camaro master cyl (1+1/8" bore) like THIS ONE from napa.

For a 67/68 4-piston type of deal, I think you'd want a 1" bore job for front disc/rear drum. Not sure of any "off-the-shelf" master cyl that really meets this, but you could try a 68-76 corvette w/ manual brakes (it'll have the 1" bore and bolt right up, but since it's set up for rear discs, you may want to add a 10lb residual pressure valve in the rear brake line).

Either way, you'll definitely want a proportioning valve in the system. Either install and adjustable job or (since it sounds like you may need to re-plumb the lines from the master cyl to distribution block anyway) you could replace your stock dist. block with a modern "combo valve" which has the proportioning and metering valves built in...

[Calpantera]

Thanks T...

Bill

[Calpantera]

OK so I pulled a wheel and it has single piston calipers, I searched for the casting numbers on the net but still cannot ID them. The say Delco Moraine 6478 510 (I think)
Here is a pic of the drivers side


Bill

[Calpantera]

Are all M/C's the same for early chevys with single piston front disc and rear drums?
Does anyone have a part number or year model for a combo valve?
I want to order the parts tomorrow so I can work on it on the Holiday Wed.

Thanks!
Bill

[TMessick]

Looks like you probably have the 2+15/16" calipers and 11" rotors, but can't be 100% sure without measuring.

There are a few different master cyls out there for the "stock" type 69-76 disc/drum setups depending on vehicle and application. You'll want a master with a "deep" pushrod hole, a 1+1/8" bore, and a larger rear reservoir. You should also get a disc/drum one that has the residual pressure valve in the rear outlet. That '69 camaro power disc master cyl that I linked should work well for your app.

For the combo valve, a lot of different places will sell a "universal" type disc/drum valve (MP brakes, CPP, inline tube, etc.) A combo valve would replace the "stock" distribution block, but you'll need to tweak the hard lines to get everything to line up (the outlets are in a little different spot compared to stock). Here's one example from Speedway Motors: http://www.speedwaymotors.com/Disc-D...alve,9878.html

Good luck!

[Calpantera]

Thanks T, I will confirm the measurments on the the rotors and pistons tomorrow and get the M/C you suggested, how do you know I will need the deep hole, for some reason I thought the deep hole was for power brakes only. Hopefully I will be able to find the proper lines in the right lengths and sizes without having to flare 'em myself.

[Everett#2390]

For deep hole measurement, you will have to pull off the m/c, you can do it without disconnecting the lines, and measure the length of the pushrod from the mating surface of the firewall.

This will give you a reference to start from.

[Calpantera]

I decided to add some fluid to the M/C to see if the calipers leaked (It was empty on that side) and then I pumped up the pedal. Now the pedal has no travel. I had converted the car from an automatic to a 4 speed so I checked that I had the rod in the right hole on the pedal and it is in the upper hole. I then unbolted the M/C from the firewall to see if it had a deep pushrod hole and it appears to because I could not get the rod to clear the M/C. I am just going to yank the M/C since I am replacing it anyway. My question is does anyone know what the correct rod length should be? The old auto pedal assembly that I took out looked to be some bastardized cobbled together thing and I am not sure if it has the right rod. I think I left the rod in the donor car when I got the pedal assembly.

Thanks!
Bill

[zdld17]

I just did a rear drum to disc conversion and was measuring the plunger depth hole, seem 1.750" depth was what I got . This was with factory front disc brakes.

The prop valve set up that was mentioned is exactly like the one you can get from Matts or Rightstuff.

I have a pair on one piece stock part number rotors left over after going to the drilled slotted, two piece. Also have a very good rear set of drum brakes with factory part # stamping, If any of you numbers guys are interested. Also have the round metering device.

Seems when I converted, Matts sent me a 4 port master cly for this setup, I only needed two so I plugged the other two holes. I am finding out that this m/c was for a 4 wheel disc brake Vette. Well, it began leaking from the plunger port and Rightstuff made it good by sending me the two port m/c. This was exactly like the master cly I took off for front disc/rear drum set up. But it works well.