Power Brakes & Power Steering Fluids : 1956 60 Series Buick Century

[killy_4_u]

Hi. I just had my original Delco-Moraine vacuum booster / master cylinder rebuilt, and while I was at it I had my power steering gear rebuilt.

 

Does any one know what fluids I should use? I always used Dot 3 for the brakes and Transmission fluid for the steering gear.

 

I think the Dot 3 is still correct but the fluid that came back in my power steering gear was clear - not red. Did they use something better than transmission fluid? What SHOULD I use?

 

Edited May 19, 2016 by killy_4_u
Mis-spelled word. (see edit history)

[SpecialEducation]

Unless you are replacing your ENTIRE brake system, stick with DOT 3. 

 

A large variety of hydraulic fluids fluids will work fine in the power steering systems. Transmission fluid is really overkill for the actual requirements, but it's relatively cheap and common. 

[killy_4_u]

Thank you! Is there any reason NOT to use transmission fluid? Is there something better I should consider?

 

[Paul Falabella]

I have used Dex/Merc in the tranny and P/S, so far so good.

[50jetback]

Who did you get to rebuild your P/B unit?

Do they have a website I can contact them on? 

[killy_4_u]

There are a few places that will do it. Even the most sought after classic car mechanic in my town didn't want to touch the Delco-Moraine. If you decide to do it let me know. I can share my headaches with you so you don't suffer the same. But for now at least realize that the power steering gear needs removed to get your master cylinder out! Which is why I decided to rebuild the steering gear while I was in there. It took me a half day for the de-install and a half day for the re-install so still not too bad. 

 

ABS in California does it for about $240 + shipping. Basic rebuild. 1 year warranty.

http://www.abspowerbrake.com

 

Then there's Apple Hydraulics. Rebuild and sleeved with limited lifetime warranty for $485 + shipping.

http://applehydraulics.com/brakes

 

I chose White Post Restorations. Rebuild and sleeved for $475 which includes shipping with an excellent lifetime warranty. Long time family business. Talk to Billy- he'll hook you up.

http://www.whitepost.com

 

[SpecialEducation]

4 hours ago, killy_4_u said:

Thank you! Is there any reason NOT to use transmission fluid? Is there something better I should consider?

 

 

I know of none.  The '56 Buick owner's manual specifically states to use the same fluid as the Dynaflow Drive.  Stability in a wide range of temperatures is the primary concern, and Dex III equivalent is much better than what was available in 1956.

I have heard that Dex IV is not good for systems not designed for it, but I don't have data on that in front of me.  I think it is super-low viscosity, making it poor for keeping high speed bearings lubed in older systems.  If I'm wrong on that, someone will be along soon to correct me...

[Beemon]

The only difference between Dot3 and Dot4 brake fluid is boiling point, but Dot4 will only be helpful to you if you do a full bleed, otherwise it adopts the characteristics of Dot3. Personally I use Dot4 because the brake line goes underneath the low part of the oil pan and the friction action of the brakes already build up heat to begin with, so raising the boiling point puts ease of mind.

 

As others have said, I've only ever used ATF fluid in the PS units. You will need to flush your PS system before filling and bleeding, however, because I think the fluid is to keep the reservoir primed. I got both units rebuilt by Lares Corp and had to flush both units until it was the ATF red coming out at a constant rate.

 

Your master cylinder looks great by the way. I rebuilt mine and painted it like that a few years ago, doesn't look as shiny anymore.

Edited May 20, 2016 by Beemon (see edit history)

[NTX5467]

CONSIDER that "transmission fluid" of 1956 is NOT what it is now.  The original fluid for "back then" was "Type A" and possible "Type A, Suffix A" fluid.  I believe it is clear, rather than red? 

 

IF the clear fluid is not Type A atf fluid, then it's probably GENUINE power steering fluid.  Possibly even the current GM power steering fluid, especially if it's got a slightly waxy look.

 

Type A atf is still around, like at some convenience stores or older auto supply stores.  Sure, the later Dexron-family fluid superceeded Type A, BUT every car I've had which spec'd "power steering fluid" which had "red fluid" in it . . . seeped and leaked until I got the red stuff out and genuine GM power steering fluid in it.  The viscosity might be similar, but the additive package is not.  It's about what kind of seals and other rubber items are in the system.

 

Ford's Mercon V atf states on the can that it can be used in their power steering units, yet GM has had a specific power steering fluid since about 1961.  Same for Chrysler.

 

I concur with Beemon on the brake fluid.

 

NTX5467

[Beemon]

While I don't doubt the abilities of GM power steering fluid, and it's most likely not an issue with modern seals, but it was suggested to me that I use the same type of fluid that was originally used - ATF fluid, simply because the pump and box were engineered for that specific fluid. You are right that fluids have significantly changed since 1956, but modern power steering pumps and assemblies are engineered for PS fluid. From what I was told, it just never occured to me to use PS fluid.

[NTX5467]

In more recent times, there are several GM PSF available.  The "normal" PSF has a little waxy look to it.  There's also a "cold climate" PSF for some Corvette applications (which I suspect is semi-synthetic).  Valvoline also had some semi-synthetic PSF a while back (variable availability) that was "the fix" for some GM steering racks which were noisy.

 

I agree that if the system was designed when Type A ATF was in use, that's what needs to be in it.  Might take some effort to find it, but it's still around.

 

NTX5467

[60FlatTop]

Torque converters run best with whale oil. It is going to be hard to get that these days. If you drain a tranny that has been sitting a long time and you get close to a full serving you might want to have it tested, strained, and filtered to put back in.

 

I use the dex//merc, though, and don't notice a lack of performance.

Bernie

[killy_4_u]

On ‎5‎/‎20‎/‎2016 at 9:10 PM, Beemon said:

The only difference between Dot3 and Dot4 brake fluid is boiling point, but Dot4 will only be helpful to you if you do a full bleed, otherwise it adopts the characteristics of Dot3. Personally I use Dot4 because the brake line goes underneath the low part of the oil pan and the friction action of the brakes already build up heat to begin with, so raising the boiling point puts ease of mind.

 

As others have said, I've only ever used ATF fluid in the PS units. You will need to flush your PS system before filling and bleeding, however, because I think the fluid is to keep the reservoir primed. I got both units rebuilt by Lares Corp and had to flush both units until it was the ATF red coming out at a constant rate.

 

Your master cylinder looks great by the way. I rebuilt mine and painted it like that a few years ago, doesn't look as shiny anymore.

 

Beemon, or anyone, do you have any tips for bleeding the brake system?

 

I was told that the unit does not need to be bench bled which is good because I already have it in the car. 

 

Do I just fill the sucker with fluid and start bleeding at the furthest wheel cylinder? Or does something else need to happen first?

 

I have the reservoir filled and I started pumping the pedal to see if it would start pressurizing before bleeding but it isn't pressurizing so I don't want to start bleeding until I figure this out.

 

Also the brake lights aren't working now though I hooked them back up the way they were before removal. I'll deal with that after bleeding.

Edited May 21, 2016 by killy_4_u (see edit history)

[Beemon]

The master cylinder does not need to be bench bled because the fill reservoir introduces fluid to the master cylinder at its highest point so air bubbles cannot be trapped.  You need to keep filling until the bubbles stop, then bleed the brakes like normal. The stop light switch will not work if air is in the system. If it doesn't work after bleeding, then it needs to be replaced. Because it is part of the hydraulic system, if it does need to be replaced then the system needs to be bled again.  I personally would not reuse the old switch.  Napa sells the pressure switch and is readily available. 

[old-tank]

Try not to pump the brakes.  When I do it, it seems to create foam that is hard to get out of the system. Four or five slow cycles of the pedal and refill.  If brakes are not real good after this, you may have to tap the master cylinder and wheel cylinders with a hammer to dislodge trapped air bubbles.  A vacuum bleeder has never worked for me...others may have better luck.  Instead I use a modification of the old 'tube in a bottle of fluid' technique and can do it alone.

[Beemon]

Surgical tubing and Coca-Cola bottles work pretty good. Plus you have to drink the coke, so you get a nice refreshment. 

[SpecialEducation]

We put in a new switch with the MC overhaul, and it wasn't right.  It took a LOT of pressure to get the lights to come on.  New switch, re-bleed, marginally better...

 

Now we have a modern style mechanical switch clamped to the steering column.  Much more reliable.

[Beemon]

That's actually really interesting, maybe your contacts needed to be sanded? I just bled my system Saturday night and used a pressure switch from NAPA no problem. I had been using a push button style switch that I also had clamped to my steering column back when I went to a dual MC but recently just swapped it back out for the original due to performance issues. I also replaced the switch contact with one from NAPA since mine was pretty corroded. To be fair the system only worked for five minutes before the first and second seal broke in the MC and fluid began dripping from the bypass hole... guess I should know better with it sitting dry on the shelf for the last couple years...