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Daniel G
Crazy Amish Guy
Joined: April 23, 2004
Posts: 828
Location: Central Alabama Amish Country
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 Posted: Thu Mar 20, 2008 12:47 am Post subject: T2 Early/Late Front Disc Brake Differences & Parts |
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Ok...I have searched this information, but I cannot find all the answers I am seeking...
I know that the '71-'72 front disc brake setups are different that the '73-79 stuff, but what are the exact differences between them?
What parts can be interchanged between the late and early disc brakes?
Is there any benefit at all to converting from the early front discs to the late front discs? Is there anyone who has done this? Would the spindles need to be swapped for the later ones as well as the brake stuff?
Finally, what about the '71 rear brakes? The early 1971 models used the same wheel cylinders as the pre-'68 models, and the late 71's used the same stuff as the '72-up bays, right? If so, are the early '71 drums separate from the hubs like on the rest of the late bays? And again, would it be worth it to just swap the early '71 parts for the late drum setup? Would everything from the backing plates out need to be swapped?
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Blaubus
Samba Member
Joined: October 25, 2003
Posts: 5153
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| Posted: Thu Mar 20, 2008 3:18 am Post subject: |
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| Is there any benefit at all to converting from the early front discs to the late front discs? Is there anyone who has done this? Would the spindles need to be swapped for the later ones as well as the brake stuff? |
the only advantage is that the brake pads are thicker, so they last longer. the brakes are NOT stronger. the pads do not have a larger contact area.
about interchangability, the hubs are the same for all 71-79. also the rims and brake hoses are the same
many people have converted form 71+ to 73+ brakes (thinking they would be stronger), and to do so requires that you change the rotors, spindles, calipers, caliper bolts, and backing plate. the rotors are the same diameter, but have a slightly different offset.
| Quote: |
| Finally, what about the '71 rear brakes? The early 1971 models used the same wheel cylinders as the pre-'68 models, and the late 71's used the same stuff as the '72-up bays, right? If so, are the early '71 drums separate from the hubs like on the rest of the late bays? And again, would it be worth it to just swap the early '71 parts for the late drum setup? Would everything from the backing plates out need to be swapped? |
wheel cylinder changed between 71 & 72, whereas drums changed one year earlier, between 70 & 71. so yes ALL 71 drums are seperate of the hub. this combination of changes made 71 shoes unique, one year only.
again, no advantage in swapping, except that the german wheel cylinders are cheaper for 73-79 by about five bucks each. no need to change backing plates if you really want to do this. they are all the same from 71-79 |
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Matt G
Samba Member
Joined: December 19, 2007
Posts: 77
Location: Tidewater, VA
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| Posted: Thu Mar 20, 2008 7:45 pm Post subject: Early/Late Disc Brake Differences and Parts Interchange |
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Daniel,
The major differences between the two brake systems are highlighted in Bentley, Chapter 8, Page 15. The 73 and later models have a larger brake caliper and 14mm rather than 10mm thick pads. The caliper mounting bolts increased in size from M12 x 1.5 to M14 x 1.5 and the tightening torque increased from 72 ft/lbs to 116 ft/lbs. The brake disc, steering knuckle (spindle) and splash shield also changed.
Here are some pictures illustrating the change in splash shield:
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424678 and
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424677
Here are some pictures illustrating the difference between the spindles (knuckles):
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424670;
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424669;
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424668 and
http://www.thesamba.com/vw/forum/album_page.php?pic_id=424667
Not mentioned, but worthy of note, the master cylinder also changed in 73 (the 71-72 style is NLA) and by mid-model year 74(?) the brake booster got bigger (in diameter)
Essentially, VW made the front brake system more robust.
The rear hub and brake drum are separate in 71+ buses, but sometimes they rust together so well as to fool the novice into thinking they are one piece.
As for retrofitting the later style to the rear of a 71, yes, it can be done. Here is a picture of the result: http://www.thesamba.com/vw/forum/album_page.php?pic_id=424681
If I were to do it again, I would retrofit the Vanagon rear brakes to the bus (if only to keep one brake style in bench stock). Karl, an advocate of this retrofit, has outlined the procedure both in the Samba (use the search) and on the Type 2 List.
Hope this helps,
Good Luck
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Matt
'90 Vanagon GL
'81 Vanagon
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Blaubus
Samba Member
Joined: October 25, 2003
Posts: 5153
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| Posted: Fri Mar 21, 2008 5:26 pm Post subject: |
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Essentially, VW made the front brake system more robust.
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the only thing that is more robust about the front brakes is the caliper mounting bolt and its torque. and there is nothing about the brake assembly, that would explain this change:
the caliper became larger to provide more room for the thicker pads and longer pistons. but the caliper piston & bore did not change diameter.
the rotor did not change diameter or thickness, neither did the hub or wheel bearings or spindle shaft diameter
the master did not change, only the resevoir inlet pipe orientation. master part number is the same, 211-611-021AA , from 71-79. that number and year range has never changed. (only) wolfsburgwest will try to tell you that the 71-72 is NLA, but all the other suppliers will tell you they are the same. when you ask WW what is different, they will tell you its only the resevoir spacing. but when i compare the 71 OG resevoir to the 78 OG resevoir, they have the same spacing.
the booster on my 71 is 1/4" smaller in diameter when compared to the 73 booster. and IMO this may have been changed to compensate for less vacuum created by the dual carburated 73 engine. according to the bentley manual, the dual carb engine has a lower compression ratio. in addition, two throttle plates instead of one, and shorter intake manifolds (lower fluid resistance), all resulting in less vacuum.
so really, if you want more braking power, it is the booster you might want to change, not the calipers. also, the use of larger caliper bolts may have been a legal consideration, or perhaps a concern that during a brake lock up, the heavier type 4 engine will put more stress on the bolts and bolt holes. these are the most highly stressed areas of the caliper.
Last edited by Blaubus on Sat Mar 22, 2008 7:17 am; edited 2 times in total |
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Daniel G
Crazy Amish Guy
Joined: April 23, 2004
Posts: 828
Location: Central Alabama Amish Country
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