New brake lines for 52 coupe de ville

[Omarine]

Hello everyone,

Now that the 52 is running reliably, i plan to install the winwood dual master cylinder.

It seems like a good time to replace the steel lines.

I might install Manual disc brakes down the line but not at the moment.

That said, the disc brakes ive used before take 3/16” steel lines and The stock drums take 1/4” lines.

Now that im going to plumb separate lines front and rear to the new MC, how will drum brakes react if i use 3/16” line to the drums instead of 1/4”? I’d prefer to do the lines only once.  I think 1/4” is needed when one brake line feeds both front and rear, but thought id ask for anyone’s experience.

On a side note, just finished the upholstery.
Thanks, cheers
Oscar

[savemy67]

Hello Oscar,

If I had to use an adjective to describe your upholstery, I would use "luscious".  Nice job.

Hydraulic force is a function of cross sectional area.  Cadillac engineers calculated the areas of the master cylinder piston, the wheel cylinder pistons, the swept area of the brake shoes, and the weight and speed of the car to help determine the volume of fluid necessary, and the size of the lines.  The entire braking system was engineered to stop the '52 given its weight, and anticipated driving conditions.

When installing a dual master cylinder from Wilwood, what does Wilwood recommend?  If the new dual M/C is not power assist, the existing line size is likely OK.  If you install manual discs in the future, will they be at the front only?  If so, a proportioning valve may be needed.  Why manual discs, and not power assist?  Again, the aftermarket brake vendor should be able to explain the engineering behind their system, and recommend the appropriate line size.

Respectfully submitted,

Christopher Winter

[Omarine]

Hello Christopher,

Thanks for the reply and the compliment!

The wilwood is 1” bore and the outlet fitting sizes are for 3/16” lines. I guess i could call their tech line. I hear a lot of comments about upgrading to the dual MC but i dont actually know of anyone who runs one.

I wanted to keep the installation simple So i didn't want to add power assist because of the extra work and expense since some cars like old vettes were manual disc and worked well.  Drums work well too but was looking for some more power the other day at a red light. I do think discs up front only are more than enough. I also have a 61 impala that i converted so im comfortable with the job but that had 3/16” lines to the front drums after a section of 1/4” line that fed the distribution blocks because that was also a one circuit MC....

Cheers
Oscar

[The Tassie Devil(le)]

G'day Oscar,

I must remark on the Corvettes not using Power Boosters for their 4 wheel disc brakes in some cars, and report that I did a RHD Conversion on as '68 Corvette that was fitted with just a Master Cylinder, and no power assist.

As always before I do any conversions, I test drive the vehicles, and I must say that this Corvette was a total "DOG" to try and stop from any speed.   I virtually had to place both feet on the brake pedal to get it to stop, and couldn't understand why Chevrolet could build such a performance car with such poor, and dangerous brakes, plus, it was an Automatic, so limited engine braking.   I would add that it would be very difficult for a slight statured person to avoid a rear-ender.   When the conversion was complete, with a booster, the car was safe to drive/stop.

If you are going to go for front disks, then for safety, a brake booster is a must.

The way most disc brake calipers are made, there would be ones that needed a boosted system, and others that did not.

One way to test the poor quality of a non-boosted system is to try and stop a boosted car, with the engine off and a drained booster.   Boy, the difference is huge.   A bit like trying to steer a power steering car when the engine stalls, and no power.

Plus, don't forget that there are three types of Master Cylinder.   1 for all drums, 1 for disc/drum, and another for all discs.   And you cannot miss-match them.

Bruce.

[Omarine]

Thanks Bruce, this wilwood MC is interesting because it has residual valves built in. Then you remove one if its for a disc application.

As for vacuum assist, with this car im not sure where it would mount, etc...

Cheers
Oscar

[The Tassie Devil(le)]

Oscar,

We used to use a remote booster to assist us in braking way back when.   Looks like they are still available, and probably available in USA?   Mount them anywhere.

https://www.onlineautoparts.com.au/products/New-PBR-Universal-Vacuum-Brake-Booster-Unit-Power-Hydraulic-Operated-suit-Disc-Drum-System-VH40/ZPN-11585_

Not cheap, but I have sold a couple of used ones in the past.

Bruce.

[Roger Zimmermann]

From the nature of the disk brakes, they are less efficient than a drum brake with the same hydraulic pressure as drums are self-energized. A Corvette with disk brakes and no power assist may be OK (Bruce is telling the contrary) but a Corvette is much lighter than a Cadillac.
At the end, you may have a car which less safe than the original set-up.

[carlhungness]

Bruce seems to have quite a bit of knowledge concerning braking and my initial question is, I want to use the C462 Hydro-Vac at this stage and can I use my stock
master cylinder. I believe the lines going to the Hydro-Vac are larger than the stock LaSalle.

[Omarine]

Well my brake lines appear to be in good shape and i will re build my stock master cylinder for now.

My bright idea of installing the wilwood dual chamber remote master cylinder didn'tpan out. The Scarebird bracket wont work on my car Without lots of modifying and trial and error. Laying on my back just isn't enough space to get a good feel for what’s going on under there.