Packard Forum Index » Pre-War (1899-1942)

Dave, how great is it to have someone on tap who is so well-informed on the Perrot brake system. Many thanks for your commentary.

Thanks Dave Great info. I would be lost without it.To-morrow I'll go and pull the drum and see how play I have in the Perrot system. Assuming there is, how is the best way to repair this.?
Dave does it matter if the shaft is sitting a little higher, where the ball end sits , at the frame than were it comes out of the drum, as the body weight is not on the chassis yet, also the shaft sits a little ahead at the frame vs. the drum end??
Thanks ever so much Ed

Owen_Dyneto & Big Ed,

I'm glad I could be of some help.

The "usual" areas where I've seen wear is the pin and hole in the long shaft that the brake lever is connected to and the hole in the short shaft that slides into the shaft that is connected to the cam that operates the primary and auxiliary shoes.

The short shaft and pin is located inside the spring loaded dust cover on the top of each front wheel backing plate. If the pin is worn a replacement can be made out of a good quality tool steel such as AISI/SAE 01 or more commonly known as A-1 tool steel. This is readily available in small diameters. One source is mcmaster.com or most machine shop or tool supply house.

If the hole in the long or short shaft is worn you can ream the hole slightly oversize. Once again mcmaster carries hand reamers. If you get the hand reamer do not turn it counterclockwise as you are cutting, you may break the flutes off the reamer. Don't try and use a drill to open the holes up, a reamer will give you a more uniform hole with a better surface finish.

Best method - hold the shaft in a machine vise and use a gage pin or indicator to make sure the hole in the shaft is in line with the spindle of the milling machine or drill press you are using. If you know someone with a tool or machine shop they can help you out.

Personally I'd wait until the body is on the frame before adjusting the brakes. I don't know what (car) body style you have, open or closed, but either way you're looking at 500 - 800 pounds that is going to be added to the frame. Not having this weight on the frame is going to change the geometry angles of the brake system and the brake cable lengths.

Regards,

Dave

GREAT STUFF Dave, My body is a 7 pass sedan, which will defintely lower the frame some what, which will level out that Perrot shaft a little more in line. How important is it that the Perrot shaft is reasonably level??
I'll check those pins for wear and than lower the body on the frame, but that will be a while before I get to that.I'll keep you posted.
THANKS AGAIN Ed

Dave & Owen &? I have taken the drum off to check the play , when I hold the cam tight, there is some movement, approx. 1|4 inch were the brake cable ties in. Is that to much?
I took the Perrot unit off the car and put it in the vise to try and take it apart. I can see some play in the pin.
I can't get the dust cover off the shaft.The shaft has a collar on it that the dust cover won't slip over.It almost looks like the dust cover is on the wrong side of this collar. Somehow the dust cover has to come off,in order to slide the complete shaft out through the Perrot housing, to get the pin out? How is the best way to disasemble this unit?
Help !!!!! ED

Big Ed,

First answer - the Perrot shaft assembly sits approx. level when the car is at a "normal" ride height. I checked a eighth and ninth series and they were about the same.

Because you have the body off I would hold off on all brake adjustments until you have the body back on.

Second question - 1/4" out at the end where the brake cable attaches is not that bad, especially when you consider the distance you're from the center of the shaft, where the play is in the joint. You have three areas where the play adds up, long shaft to pin, pin to short shaft, and short shaft to the cam that operates the primary and auxiliary shoe.

The dust cover (closest to the front backing plate) over the Perrot universal joint has a "C" clip type collar that fits into a groove in the shaft. Pull the spring back from this collar and you should be able to remove the "C" type clip. When you do this you will release the spring that holds the dust cover against the mating other half of the ball.

I've dealt primarily with eighth and ninth series cars so all the info I've given is based on those models. I believe the Perrot type system was used on Packard's from '25 on, your seventh series may have some differences.

Good luck,

Dave

Thanks Dave Glad to hear that 1/4' is not to bad,I think I'll put it all back again, put the body back on and see what that does.
Dave are ther two dust covers on each unit as you say (the dust cover closest to the front backing plate), mine has only one, may-be one is missing? I got the 'C'clip out o.k which allows the cam shaft to slide( towards the brake drum)as the cam itself as a little larger than the Perrot housing hole.My shaft is a little diff. than the picture Fig.#N22 in the Bendix booket, it has a collar machined on it as part of the shaft and the dust cover sits on the inner side , the rest looks the same. If I can't get the dust cover off I can't slide the complete unit out through the Perrot housing to get the pin out.? AS you can tell I'm not to good on the computer yet and don't know how to place a photo on here..
If you don't mind, I'd like you to e-mail me with your phone#, so I can explain this a little clearer may-be??

Thanks again Ed dloyens@295.ca

Big Ed,

There are two slightly different designs for the Perrot shaft assembly. One design has a dust cover on the top of the front backing plate and a exposed ball stud and socket that is connected to the frame.

The second design has the same dust cover on the front backing plate but instead of a ball stud on the frame there is a shaft and bushing covered by a dust cover, that mounts to the frame.

The first design was used on later series cars, the second on earlier series.

Both designs use dust covers that are spring loaded. A dust cover is comprised of two covers, a outer and inner. The inner is fixed to the front backing plate and the outer is free to slide forwards and backwards across the inner, as the front wheel turns.

For the earlier design the inner is fixed to the frame and the outer slides up and down as the frame moves up and down on the springs.

Regards,

Dave

Thanks Dave
I was gone away for a few days,so I've just gotten your mail.
I believe that the inner dust cover is missing, the one that is removed by taking out that 'C'clip.
I think my car has the later design from your description, if that makes any sense.The picture Fig.N22 page 37 of the Bendix booklet shows a dust cover at the frame end as well, not at all like mine.My shaft has a ball at the end, which fits into a socket that is attached to the frame with about a 3" arm.
I still don't know how to remove the dust cover off the shaft part closest to the wheel.
Thanks again Ed

Ed:

The Perrot assembly on your car has parts installed in the following order from the half sphere joint toward the middle of the car: First is a brass cup that acts as a shield to keep dirt out and to make the motion smooth. Next is a smaller cup with a flange on the side toward the middle of the car that the spring seats on. Next is the spring. Next is a retainer that fits over the end of the spring. Next is a circular clip that nestles in a recess in the inner end of the smaller cup and in a groove in the shaft. If you push the spring retainer toward the outside of the car, you will see the clip. Work the clip out of the groove and everything can then slip off over the shaft. The above also answers your question about whether there are two cups - yes there are. The brass one is readily available from the usual suppliers. The smaller should be relatively non-wearing. If you are missing one or both of the smaller cups, I may be able to supply them. If you find that the universal joint parts are worn, I may have some of those also.

Good luck.

Jim Wayman
640 Phaeton