View Full Version : Temporary Front wheel cylinders?

09-20-2005, 12:31 AM
I have a 1970 Javelin, with a 304, and Drum brakes on all fours. I Know a disc swap is straight forward and doesn't require 'Alotta Money', but I don't think I know her very well. The shoes are receant and the car was stopping just fine for me. Now, my front brake wheel cylinders need some attention.

Wheel Cylinders are just as cheap to buy new than they are to rebuild, right? Apparently not the case for 1970 Javelin, I am finding prices like $50 plus, each ( with kits not much cheaper!). Have I been under a bunch of rocks? shouldn't almost any 1 3/16 bore kit be the same? Is there a proportion valving thing going on at the cylinder? Whats the special deal with these cylinders??
Am I not thinking again? They warned me about polishing too much Aluminum!! :confused:
Anybody got a cross reference to another part.
Federal Mogul- Left F45960 , Right F45961
Raybestos- Left WC37126 , Right WC37125

Maybe I do the swap.. anyone? ,anyone? :eek:

10-08-2005, 09:27 AM
No comments or opinions? I guess it is a BRAKE question, and that means if I do some sort of mickey mouse short cut and it doesn't work I would have probably just killed someone, or at least smashed my ride..
How about discussing the principle of hydraulic brake systems, concentrating on the wheel cylinder perhaps? In a 4 wheel drum system, is there an issue with proportioning, Front to rear, that requires metering or control (proportioning valve?) ?

I realize that in a Disc/drum system, there is an obvious difference in fluid volume, just by looking at the master cylinder (bigger resevoir for front circuit compared to rear). Let alone the actual different method/type of actuation between disc and drum.

But in a 4 wheel drum setup, would a change in one circuit, like an increase/decrease in wheel cylinder bore diameter, have any substantial effect on the other circuit. For example, a swap from a Gremlin 6Cyl. AMC rear end to a V8 AMC rear end. Would this require a anything to change at the master cylinder, because the wheel cylinder bore changed from 13/16th to 7/8th, (a 1/16th of an inch increase). Is this too small of a difference to warrant any attention?

Now would bigger be better? for example again, 73 Matador front bore is 1 3/32nd compared to 73 V8 Gremlin,Hornet, and Javelin bore of 1 3/16. Is the Matador's bore different for more stopping power or because it's rear wheel cylinder bore is 15/16th ,Vs. Javelin @ 7/8ths.

I figured spending time pondering these questions was more important than actually fixing the darn brakes. NOT! :rolleyes:

I guess I see why changing to disc/drum is worth the effort!!

10-20-2005, 03:39 PM
Wheel cylinders have a special finish on the inside. You can hone them, but you can never get that special 'smooth' finish a new one has at home with a hone. If the car is a 'keeper' I would go for new wheel cylinders. It's well worth the money to just replace them.

There is no proportioning valve in a drum/drum system, it's not needed. The relationship of MC piston size to WC piston size is one of mechanical advantage.


Pascal's Law states that if pressure is applied to a non-flowing fluid in a container, then that pressure is transmitted equally in all directions within the container.

So bigger wheel cylinder to MC piston size equals MORE mechanic advantage. Yes, it does matter. For example if you put 6 cylinder wheel cylinders on the front (front is approx. 60% of braking in a rear wheel drive car), I can promise your v-8 car won't brake as well.

Bendix supplied the brakes to AMC. The front wheel cylinder size is 1 3/16" inch for v-8 cars...that's correct. You can get the rear v-8 wheel cylinders for about 10 bucks each (think they 7/8") but the fronts are quite a bit more expensive.

Yes, this is just a fact.

12-24-2005, 09:11 AM
I ran across something in a Jeep Military PU site talking about using a differrent, more availible, Wheel Cylinder unit, I think that there was a slight modification to the backing plate for the mounting bolts. This is the kind of info I was toying with about the Javelin setup. I can't seem to come up with enough specification information on other cylinder applications.

I almost got some info from the Bendix website, I asked their tech-line about the interchangability between part#'s 33700/33701 (AMC Front wheel cylinders, Rght/lft), and part#'s 33945/33946 (Ford F250 Daully PU, Rear wheel cylinders, Rght/Lft). Both have 1 3/16 bores, 3/8-24 Line fitting, and have physically similar type mounting, (two bolts inline, with a circular area passing through the backing plate). Hoping for dimensions, I recieved a PDF from one of their manuals showing a drawing of the two but no actual dimensions, ARrrrrrGGGH!. Spending a little extra and converting over to disc is really startiing to sound so much easier, but I want to figure out this Modification/Interchange idea. just for my own sanity-sake. Besides the Ford units are about 1/4th the cost!

It appears that the information highway (internet) is still not quite as speciific as a few good old parts manuals for actuall details.. :eek: