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steven 123

mechanical brakes

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Year, make, model.........and a photo wouldn’t be bad either..........

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A shop manual for your car should give you step-by-step instructions.  It's easy to get it wrong if you don't follow the correct procedure.

 

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Proper adjustment of mechanical brakes is critical to efficient safe braking. And, as others have said, cars are different. Good lubrication helps a lot. Understanding the angles of leverage helps figuring out adjustment. For every general rule, there are exceptions. However one general rule is that maximum efficiency is when brake rod and lever are at 90 degrees (right angle) when the brakes are applied. When the foot is off the pedal, levers should lay back a bit (how much varies a lot from car to car). 

Internal expanding and external contracting also makes a difference in how they operate, and exactly what is proper adjustment. Mechanical brakes should generally lock the wheels at about half way down the pedal travel to the floor. Lower becomes risky with additional wear. Higher may cause the brakes to drag slightly and get too hot when not being used.

 

Some cars have equalizers in the linkages. They compensate for uneven wear or ground. Proper adjustment of the equalizers generally should pull both sides equally on smooth level ground. Again, nice right angles are usually best. Some cars (most notably the model A Ford!) do not have equalizers. One must make certain all braked wheels begin braking at about the same pedal point, and also lock at the same pedal point. Many cars can have more than a  couple dozen different cams levers and adjustable brake rod ends (clevises), all need to be set up in concert. Some early cars may have only a half dozen.

 

Four wheel mechanical brakes, properly maintained and adjusted, can work just as well as four wheel hydraulic brakes. Two wheel mechanical brakes should work at about 40 percent that efficiency. With a little extra care while driving, plenty adequate for basically safe time enjoying life in the slow lane.

 

Mechanical hand brakes generally work about the same. I recommend people practice a few times using the hand brake for stopping, just to be prepared for that emergency that you may hope never comes.

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The brake adjustment will be covered in the cars owners manual. Maybe some one can copy the page and post it here.

Post down in the Chrysler Products General section and ask about adjusting manual brakes.

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Mechanical brakes are fine as long as all the "slop" in the system is eliminated. All the levers, bushing, cams are in good shape. You might evaluate you brake's while you are working on your car. Quick question, you say that your 1927 Chrysler has mechanical brakes on the rear only?

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For those new to 2-wheel brakes, please note one should be prepared to use BOTH service (foot) brake and hand brake for a "sincere" stop.  For my two 2-wheel brake cars (and one car now long gone), the external contracting band is about 3 times as powerful or effective as the internal expanding shoes, BUT the externals lose a great deal of efficiency in the rain, which our cars rarely see.  On those same three cars, the factory installation was that the service (foot) brake operated the internal, less powerful brakes, essentially mandating that both brakes be used together.  Over the years, SOME cars have had their controls reversed, so that the foot brake operates the more powerful externals.  Pay attention to the factory design, described in your OM, and compare to how your brakes are arranged today. 

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Just now, 46 woodie said:

Mechanical brakes are fine as long as all the "slop" in the system is eliminated. All the levers, bushing, cams are in good shape

YES!  Check your clevis pins and their yokes for wear as indicated by "slop." VERY important that you fix as necessary to remove "monkey motion" (a technical term of the mechanical brake era). 

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hmmm....I understood all Chrysler products had hydraulic brakes from the get go in 1924. Am I missing something?

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1 minute ago, Gunsmoke said:

hmmm....I understood all Chrysler products had hydraulic brakes from the get go in 1924

Right you are, Gunsmoke!  But some cars had external contracting brakes

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3 minutes ago, Gunsmoke said:

hmmm....I understood all Chrysler products had hydraulic brakes from the get go in 1924. Am I missing something?

Hydraulic brakes on the rear only on some Chryslers until 1928.

Edited by keiser31 (see edit history)

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12 hours ago, Gunsmoke said:

hmmm....I understood all Chrysler products had hydraulic brakes from the get go in 1924. Am I missing something?

yes my 1297 is a model 50 which is the base model, I saw a 1924 with mechanical rears.....funny enough is that  I saw a 1926 model 60 with hydraulic brakes.....I think they changed about this time and the chepo mdels got hydraulic las

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Yes the 1927 model 50 4 cyl cars had 2 wheel mechanical rod brakes as standard on the rear. George Dammans book "70 years of Chrysler" says 4 wheel hydraulic brakes were an option on the model 52 in late 28 cars. 

 I rebuilt both a 1927 model 50 with 2 wheel mechanical brakes and a 1928 model 52 with 4 wheel hydraulic brakes. I also had remains of 2 further model 50 cars, and both of them had bits of the original 2 wheel mechanical brakes.

There has been conflicting articles about some 4 cyl cars in years 1926/8, having both 2 wheel hydraulic and 4 wheel hydraulic brakes. One wonders if some earlier cars were upgraded by dealers.

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this is from the model 52 owners handbook, the brakes on a model 50 are identical.

Viv.

chrysler 50 brakes.jpg

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Assuming the system is in good working order, pedal moves freely, no obstructions on the rods, and return springs bring rods and cross shafts back to position. An important adjustment is the position of the wheel's lever. The Brake Rod should be slightly less than tangent/perpendicular (90 degrees) to the lever and when applied, the lever moves tangent (at 90 degrees) to the rod to provide maximum force to the lever. A common misadjustment is having the lever at 90 degrees when at rest and the lever goes beyond 90 degrees when applied. Every case is different, if adjusting the shoes can't make the lever in the correct position, it maybe necessary to move the lever on the shaft's splines one tooth to get it in the correct position, due to wear.

 

Mechanical Brake Adjustment.jpg

Edited by Friartuck (see edit history)
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Some cars use open cables and no side-to-side tension balancing pivots. My English Austin is that way.

 

To get even braking you adjust the side-to-side tension by sound, just like tuning a string musical instrument.

Once the cables are adjusted so that the levers are at 90 degrees with the brakes are fully applied, then "pluck" the mid-length of each cable like a guitar string and listen to the pitch. Adjust the tensions so that the pitch is the same for both sides and the cable tensions will also be the same. 

 

It's easy with the Austin because the hand brake lever operates all four brakes. With other systems you'll need someone to hold the pedal down.

 

And yes, mechanical brakes can work just as well as hydraulics, but only if they are set up as the factory would.

 

Paul 

Edited by PFitz (see edit history)

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For the non Chrysler folks.

Only the 4 cylinder Chrysler cars had rear only mechanical brakes as standard equipment.

All of the 6 cylinder cars had 4 wheel hydraulic brakes as standard equipment as well as the Model 58 4 cylinder.

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On ‎1‎/‎20‎/‎2019 at 7:19 PM, edinmass said:

Year, make, model.........and a photo wouldn’t be bad either..........

 

4 hours ago, 28 Chrysler said:

For the non Chrysler folks.

Only the 4 cylinder Chrysler cars had rear only mechanical brakes as standard equipment.

All of the 6 cylinder cars had 4 wheel hydraulic brakes as standard equipment as well as the Model 58 4 cylinder.

 

4 hours ago, 28 Chrysler said:

For the non Chrysler folks.

Only the 4 cylinder Chrysler cars had rear only mechanical brakes as standard equipment.

All of the 6 cylinder cars had 4 wheel hydraulic brakes as standard equipment as well as the Model 58 4 cylinder.

Mechanical brakes MUST be backed up with a very loud horn,maybe a 5 mile Klaxon.

Bob Roller

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In addition to the louder than normal horn there is the "French brake" which is

the bumper of whatever's in front of you.I had a good looking 1935 Packard

CC with mechanical brakes and they were supposedly adjusted right but to

me they felt weak.Back then I was used to brakes on a "J" Duesenberg and

maybe that was a poor comparison.

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4 hours ago, 28 Chrysler said:

For the non Chrysler folks.

Only the 4 cylinder Chrysler cars had rear only mechanical brakes as standard equipment.

All of the 6 cylinder cars had 4 wheel hydraulic brakes as standard equipment as well as the Model 58 4 cylinder.

The original Chrysler, introduced in 1924 was a newly designed, modern car with a 6-cylinder engine, 4-wheel hydraulic brakes and other advanced features. During that time period Chrysler was absorbing the former Maxwell auto company and in 1926 the Maxwell was essentially relabeled as a Chrysler, models 50 and 58. I had a 1928 model 52 and it looked almost exactly like the larger, more expensive Chrysler 62, in fact was not that much smaller, but underneath they had very little in common. The 4-cylinder model 52 had a thermosiphon cooling system (gravity operated, no water pump) and fabric universal joints and, as noted above 2-wheel mechanical brakes. It was basically a bullet-proof design and held up well, but was far behind its time design wise.

 

 

Chrysler007.thumb.jpg.2ac2949380a581a200593c30c3a8d27a.jpg

I bought the 1928 Model 52 from the original owner who was a traveling salesman and drove the car all over East Tennessee. I have no idea how many miles were on it, but it was his sole transportation for business and family until an axle broke in 1959. Interestingly he had chosen that car specifically because of the 2-wheel brakes. He was one of many at the time who didn't trust brakes on the front wheels. He thought in an emergency situation the front brakes would lock and cause you to lose control of the car. Actually, until the advent of antilock brakes the old guy might have had a point.

 

Don

 

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Hi Don. That old gent was far from alone in his assessment of front wheel brakes. I have mentioned before that Cadillac in their first iteration of 4 wheel brakes for the 1924 & 1925 V63 hedged their bet. They built a primitive mechanical ABS system which disconnected the outside front wheel brake in a turn. It works, and I wonder if any other makes had some equivalent ? 

 

That is one fine picture showing the pride of honest work your Chrysler must have felt ! In harness until 1959 !!!!!!!!

 

By the way, I love your statement regarding definition of antique. I am only slightly younger than you, having been born in 1944. To us, the only cars on the road when we were born were pre-war, and the late '30s cars we first remember riding in were "modern". My dad had a '33 Buick which I still remember, and then a '39 Pontiac. Call me a cranky old man if you want, but IMHO antique cars have exposed vertical radiators. Those were the OLD cars in our youth. I loved them then, I love them now !

                                                                                Cranky and old,    -    Cadillac Carl 

 

P.S. Maybe it should be mentioned, however, that pre-ABS proportioning valves want to lock the front brakes before the natural tendency for the rears to lock. Helps to keep the beast from swapping ends.   -   CC 

Edited by C Carl
Add P.S. (see edit history)

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