Possible sticky brake 72 bus

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72Hardtop
Old School!
Location: Seattle, WA./HB. Ca./Shizuoka, Japan
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Possible sticky brake 72 bus

Post by 72Hardtop » Mon Sep 26, 2011 12:14 am

I've got an issue that's much more noticeable since I rebuilt my front end completely. When the brakes are applied it pulls to the right. If I lift off the pedal and apply again but firmer it stays straight. I also notice that when rolling to a stop the bus doesn't stop on a roll freely but very subtly with some drag (most noticeable just prior to full stop). What I've done with the brakes so far? Both front calipers were replaced, new rotors/pads and all new rubber brake lines front/rear back in 2007. I also replaced both rear wheel cylinders in 2006.

I noticed when underneath just prior to my front end rebuild that the front right caliper had a bolt missing (lower most)...Air in the system likely the cause???

My guess is either I've got a sticky caliper on it's release or some air in the system.
1972 Westy tintop
2056cc T-4 - 7.8:1 CR
Weber 40mm Duals - 47.5idles, 125mains, F11 tubes, 190 Air corr., 28mm Vents
96mm AA Biral P/C's w/Hastings rings
42x36mm Heads (AMC- Headflow Masters) w/Porsche swivel adjusters
71mm Stroke
Web Cam 73 w/matched Web lifters
S&S 4-1 exhaust w/Walker 17862 quiet-pack
Pertronix SVDA w/Pertronix module & Flamethrower 40K coil (7* initial 28* total @3200+)
NGK BP6ET plugs
002 3 rib trans
Hankook 185R14's

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Amskeptic
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Re: Possible sticky brake 72 bus

Post by Amskeptic » Mon Sep 26, 2011 8:15 am

72Hardtop wrote: When the brakes are applied it pulls to the right. If I lift off the pedal and apply again but firmer it stays straight.
Try bleeding left caliper both bleeders bottom one first. Do it with the engine running so you can expel fluid with the assistance of the booster, just make sure you give the system time at the top of the pedal to replenish the circuit.

While down there, see if any pad is more worn than the others. All spreader springs and pins and shims installed? Tire pressures equal across the front? Tire wear similar?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

72Hardtop
Old School!
Location: Seattle, WA./HB. Ca./Shizuoka, Japan
Status: Offline

Re: Possible sticky brake 72 bus

Post by 72Hardtop » Mon Sep 26, 2011 8:22 am

All brake hardware is in place with exception of the one missing caliper bolt I replaced. I replaced both front tires and the right front had excess wear on the outer edge of the tire. The left front showed no signs of abnormal wear. Put two new Hankooks on the front after completing the front end rebuild. Bus was also aligned.
1972 Westy tintop
2056cc T-4 - 7.8:1 CR
Weber 40mm Duals - 47.5idles, 125mains, F11 tubes, 190 Air corr., 28mm Vents
96mm AA Biral P/C's w/Hastings rings
42x36mm Heads (AMC- Headflow Masters) w/Porsche swivel adjusters
71mm Stroke
Web Cam 73 w/matched Web lifters
S&S 4-1 exhaust w/Walker 17862 quiet-pack
Pertronix SVDA w/Pertronix module & Flamethrower 40K coil (7* initial 28* total @3200+)
NGK BP6ET plugs
002 3 rib trans
Hankook 185R14's

72Hardtop
Old School!
Location: Seattle, WA./HB. Ca./Shizuoka, Japan
Status: Offline

Re: Possible sticky brake 72 bus

Post by 72Hardtop » Fri Sep 30, 2011 2:16 pm

Update:


Had to replace both front calipers w/new pads and front brake hoses. All of which was done back in July 07' including the rear hoses. Flushed brake system and replaced with synthetic brake fluid as well.

All thanks to this lovely PNW weather angry9:

May have to move back to dry southern California.
1972 Westy tintop
2056cc T-4 - 7.8:1 CR
Weber 40mm Duals - 47.5idles, 125mains, F11 tubes, 190 Air corr., 28mm Vents
96mm AA Biral P/C's w/Hastings rings
42x36mm Heads (AMC- Headflow Masters) w/Porsche swivel adjusters
71mm Stroke
Web Cam 73 w/matched Web lifters
S&S 4-1 exhaust w/Walker 17862 quiet-pack
Pertronix SVDA w/Pertronix module & Flamethrower 40K coil (7* initial 28* total @3200+)
NGK BP6ET plugs
002 3 rib trans
Hankook 185R14's

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Possible sticky brake 72 bus

Post by Amskeptic » Sun Oct 02, 2011 7:52 am

72Hardtop wrote:Update:
Had to replace both front calipers w/new pads and front brake hoses.
Why? At who's recommendation? What signs pointed to having to replace both calipers?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

72Hardtop
Old School!
Location: Seattle, WA./HB. Ca./Shizuoka, Japan
Status: Offline

Re: Possible sticky brake 72 bus

Post by 72Hardtop » Sun Oct 02, 2011 3:57 pm

Drivers side seized (rust) passenger side not seized but rusty as well. Went ahead and replaced both as a set. First time I've ever ran across this but then again I'm not from the PNW either.

While underneath I noticed one of the ball joint boots has a twist in it (approx 90 degrees)lower passenger side boot. Didn't do the ball joints so I'll have to take it back to where I had them done to correct it.
1972 Westy tintop
2056cc T-4 - 7.8:1 CR
Weber 40mm Duals - 47.5idles, 125mains, F11 tubes, 190 Air corr., 28mm Vents
96mm AA Biral P/C's w/Hastings rings
42x36mm Heads (AMC- Headflow Masters) w/Porsche swivel adjusters
71mm Stroke
Web Cam 73 w/matched Web lifters
S&S 4-1 exhaust w/Walker 17862 quiet-pack
Pertronix SVDA w/Pertronix module & Flamethrower 40K coil (7* initial 28* total @3200+)
NGK BP6ET plugs
002 3 rib trans
Hankook 185R14's

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Possible sticky brake 72 bus

Post by Amskeptic » Mon Oct 03, 2011 8:34 am

72Hardtop wrote:Drivers side seized (rust) passenger side not seized but rusty as well.
I deleted your non-brake references as we are in the Technical Forums under "Brakes".
Colin
(ball joint boots can be re-twisted back with your fingers, they should have lubrication between ball joint stud and their inner surface)
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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