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-   -   Rear axle-parts identyfication (https://6066gmcclub.com/showthread.php?t=51797)

Miko February 11th, 2025 07:04 PM

Re: Rear axle-parts identyfication
 
Ok, I ordered some parts and am waiting for delivery :)

Jim A February 12th, 2025 05:11 PM

Re: Rear axle-parts identyfication
 
The brake cleaning mentioned is intriguing. What is washing soda?

Prowbar February 13th, 2025 09:43 PM

Re: Rear axle-parts identyfication
 
1 Attachment(s)
Quote:

Originally Posted by Jim A (Post 78621)
The brake cleaning mentioned is intriguing. What is washing soda?

Glad you asked Jim. See picture attached. It is sodium carbonate.
Has many uses, it is a great degreaser in when dissolved in hot water.

My dirty (blue) coveralls usually resemble the texture and color of a graphite pencil when I'm through with the job. To wash them, I soak them for a day in a bucket with hot water with a spoon of washing soda. After that they go into the washing machine.

Miko March 9th, 2025 09:31 PM

Re: Rear axle-parts identyfication
 
Houston we have a problem... The ordered parts do not fit :/ on Saturday I was working on the brakes and when I tried to install the brake cylinder, it did not fit :/.
The ordered cylinder is bigger/larger than the original one, but the mounting points are the same. Now I don't know what to do. If I trim the limiter brake cylinder will fit, but I'm afraid of the diameter of the cylinder. It is larger than the original - similar diameter is in the front brakes. Rear brakes will be to strong..
Can i mount it and for example use brake proportioning valve?

PS fotos old front brake cylinder, new rear brake cylinder and old rear brake cylinder (smallest)
[IMG]
https://ibb.co/WWQHZJCG
https://ibb.co/yBsWTHLs
https://ibb.co/nMr63MkH
https://ibb.co/DD6G0yJt
https://ibb.co/mF5fx32B
https://ibb.co/xKsBM038
https://ibb.co/vvrHpp1w
[/IMG]

James March 9th, 2025 11:11 PM

Re: Rear axle-parts identyfication
 
Quote:

Originally Posted by Miko (Post 78660)
Houston we have a problem... The ordered parts do not fit :/ on Saturday I was working on the brakes and when I tried to install the brake cylinder, it did not fit :/.
The ordered cylinder is bigger/larger than the original one, but the mounting points are the same. Now I don't know what to do. If I trim the limiter brake cylinder will fit, but I'm afraid of the diameter of the cylinder. It is larger than the original - similar diameter is in the front brakes. Rear brakes will be to strong..
Can i mount it and for example use brake proportioning valve?

If there is enough adjustment to allow the drum to go on, I would used it. Measuring the OD of the cylinder is not the right way, the ID is what important as far as power being applied to the shoes. I would not use a proportioning valve if the ID are the same or within a mm or so (length only matter if the drum can't go on with everything that goes inside is assembled).

Side note (I case you don't know): The shoe that has the most lining gets mounted toward the rear of the truck.

Miko March 9th, 2025 11:54 PM

Re: Rear axle-parts identyfication
 
Quote:

Originally Posted by James (Post 78661)
If there is enough adjustment to allow the drum to go on, I would used it.

It will be - I checked it

Quote:

Originally Posted by James (Post 78661)
Measuring the OD of the cylinder is not the right way, the ID is what important as far as power being applied to the shoes.

Yes i know it, diameter difference is 3.19 mm (28.39 vs 31.58)

Quote:

Originally Posted by James (Post 78661)
I would not use a proportioning valve if the ID are the same or within a mm or so (length only matter if the drum can't go on with everything that goes inside is assembled).

I wondered about this before, because sometimes harder braking would end up locking the rear axle while the front wheels continued to turn. Now I think the problem will be bigger

Quote:

Originally Posted by James (Post 78661)
Side note (I case you don't know): The shoe that has the most lining gets mounted toward the rear of the truck.

I don't know what it means / don't understand :)

James March 10th, 2025 01:23 AM

Re: Rear axle-parts identyfication
 
2 Attachment(s)
Quote:

Originally Posted by Miko (Post 78662)
Yes i know it, diameter difference is 3.19 mm (28.39 vs 31.58)

I don't know what it means / don't understand :)

If the new one is 3.19 mm (.125") larger, then a proportioning valve might be necessary.

The brake shoes that come in the box will have enough for one axle, which is 4 shoes. If you lay them out and compare the lining on them you will see that two of them will have more linings on them than the other two. The one with the most linings (see attachment of the right rear brake) gets mounted toward the aft side of the axle. Looking back at your original picture of the Left Rear Brake it clearly show the different, aft shoe lining is longer than the front shoe.

Miko March 10th, 2025 09:45 AM

Re: Rear axle-parts identyfication
 
Quote:

Originally Posted by James (Post 78663)
If the new one is 3.19 mm (.125") larger, then a proportioning valve might be necessary.

The brake shoes that come in the box will have enough for one axle, which is 4 shoes. If you lay them out and compare the lining on them you will see that two of them will have more linings on them than the other two. The one with the most linings (see attachment of the right rear brake) gets mounted toward the aft side of the axle. Looking back at your original picture of the Left Rear Brake it clearly show the different, aft shoe lining is longer than the front shoe.

Why is that?
In European cars, brake shoes are similar - there is no difference between front and rear on the same axle.

In my box of parts I found another brake cylinder-smaller than the original, but very close (less than 5 mm), but the inlet of the brake line has a smaller diameter, so I have to try to make new brake lines and find an end with the right thread which will not be easy-in the EU we use a different thread pitch. Model is a "profusion awc9026" can you help me with finding brake line inlet diameter?

James March 10th, 2025 03:10 PM

Re: Rear axle-parts identyfication
 
1 Attachment(s)
Quote:

Originally Posted by Miko (Post 78664)
Why is that?
In European cars, brake shoes are similar - there is no difference between front and rear on the same axle.

Model is a "profusion awc9026" can you help me with finding brake line inlet diameter?

I has been a very long time ago that I had worked on a european car and as I recalled you're right about the brake shoes linings being equal length. On an American car they're not (attached is a better picture of what I would have needed if I kept drum brakes on my 1964 1500 and it show the different between liner length). The different in length, as I recall from school, has to do with normal driving. 99% of the time you are driving forward and as you step on the brake the linings act as a wedge on the drum. As the lining wear the aft lining will wear more than the front one, so they made the aft lining longer on a single wheel cylinder design. Now that I think about the european cars that I had worked on was a dual wheel cylinders brake (two cylinders per wheel) and with that setup the linings would be equal length.

As far as the wheel cylinder specs, contact the manufacturer for it at: https://profusionbrakes.com/

Sorry if I wasn't much help.

Miko March 10th, 2025 05:03 PM

Re: Rear axle-parts identyfication
 
I am probably buy another one.
Will it be suitable for my car?

https://www.rockauto.com/en/moreinfo...t=1952&jsn=970


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