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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sat Apr 17, 2021 6:43 pm Post subject: Front Drivers Brake Hot - Thoughts? |
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Hello all,
Back around December. the master cylinder went out on our '76. We bought and replaced the master, bled the system, and the brakes seemed perfect. However, there was a new (we think new) slight binding on the front drivers disc brake when spinning the wheel. We didn't think much of it and used the vehicle locally on running errands. I would feel each wheel hub after initial drives and everything was cool to the touch.
Fast forward to today and we went on a 100 mile round trip and somehow burnt through 2/3rd tank of gas. It was a hilly drive so I thought maybe we needed a timing tune up. On getting home, I touched each wheel and all were very slightly warm (it was an 85 degree day and 50 miles) but the drivers front hub was super hot, too hot to touch.
I'm thinking either a collapsing hose on that wheel OR the pushrod on the master cylinder is ill-adjusted and keeping the brakes slightly "on". But wouldn't ALL the brakes be binding and hot? Also, super hot day could contribute to a tight caliper getting tighter?
Any ideas to test, guys?
Thank. _________________ 1976 VW Transporter, 2.0 FI Engine
Last edited by wagohn on Sat Apr 17, 2021 7:19 pm; edited 1 time in total |
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camino70 Samba Member
Joined: September 13, 2020 Posts: 156 Location: Canton, Georgia
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Posted: Sat Apr 17, 2021 7:15 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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My first guess would be a stuck caliper. _________________ Ron
1974 Westfalia
Goal: get the 914 1.7 running |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Apr 17, 2021 7:41 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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The rubber brake hoses fail from the inside out. They swell and prevent the free flow of fluid in both directions. When you press the brake, let’s just say you’re pushing 1000psi through that restriction into your brake. When you release, it’s just free flow for return so if the hose is bad, your brake will stick _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sat Apr 17, 2021 7:49 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Thanks guys. That's where Im leaning too, new hoses required. I was suspicious of a misadjusted master cylinder rod as that's the last thing we changed, but then all hubs would be hot, correct? The other three hubs were barely warm after 50 miles. Also, perhaps the slight binding on the drivers front was there for some time, but only noticed after bleeding all brakes for the master cylinder swap.
Anyways, I will jack up the front tomorrow, test both sides for binding, and, assuming the drivers front is still binding, I will relieve the bleed screw and see if the binding stops.
Thanks! I will report back. _________________ 1976 VW Transporter, 2.0 FI Engine |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Apr 17, 2021 8:10 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Front brake hoses cost less than $20 each. If you’ve already changed your master cylinder then you know how to bleed the brakes. You’ll only need to do the front since you have a dual MC so front and back are separate systems. I’d just change them since they are the next step and a whole lot easier than the step after that which is the calipers
Edit: don’t get fancy with new hoses _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sat Apr 17, 2021 8:20 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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aeromech wrote: |
Front brake hoses cost less than $20 each. If you’ve already changed your master cylinder then you know how to bleed the brakes. You’ll only need to do the front since you have a dual MC so front and back are separate systems. I’d just change them since they are the next step and a whole lot easier than the step after that which is the calipers
Edit: don’t get fancy with new hoses |
That's my plan. Thank you. _________________ 1976 VW Transporter, 2.0 FI Engine |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Apr 17, 2021 9:10 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Please update this thread when you can _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sat Apr 17, 2021 9:13 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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aeromech wrote: |
Please update this thread when you can |
Will do. Tomorrow I want to at least jack up the front and test by spinning the wheels for binding. Then order hoses. _________________ 1976 VW Transporter, 2.0 FI Engine |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Apr 17, 2021 9:17 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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You should update your profile with more info like your location _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sun Apr 18, 2021 1:55 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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wagohn wrote: |
aeromech wrote: |
Please update this thread when you can |
Will do. Tomorrow I want to at least jack up the front and test by spinning the wheels for binding. Then order hoses. |
Went on a local 5 mile jaunt. On getting home, the front drivers hub was warm/hot to the touch and the passenger's side cold. I jacked the front of the bus up and the front passengers wheel spun freely, the drivers side would not - it was similar to when you over adjust a drum brake and the wheel barely spins.
Due to the strangely warm weather we're having I left it at that. I will order hoses and by the time they get here weather should be back to normal.
Thanks, will update again, as I make progress. _________________ 1976 VW Transporter, 2.0 FI Engine |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50352
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Posted: Sun Apr 18, 2021 3:28 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Once you have driven 10 miles or so on a road that requires you to use the brakes frequently crawl underneath and loosen the bleeder on the side that is getting hot and see if there is any pressure in the line. A slow seepage of brake fluid is normal, but a pulse of fluid as you first open the bleeder is not. However if the bleeder is all clogged up with rust and dirt, you will not get a good test. |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Wed Apr 21, 2021 12:26 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Wildthings wrote: |
Once you have driven 10 miles or so on a road that requires you to use the brakes frequently crawl underneath and loosen the bleeder on the side that is getting hot and see if there is any pressure in the line. A slow seepage of brake fluid is normal, but a pulse of fluid as you first open the bleeder is not. However if the bleeder is all clogged up with rust and dirt, you will not get a good test. |
Update: The bus has sat in the garage for 2 days now and so I jacked up the front. The drivers front brake is still stopping the wheel from rotating freely - even when cold. I then removed the tire and slackened the top bleed screw on the caliper (there are 2 screws, I only slackened the top bleed screw).
The bleed screw began to slowly drip fluid, there was no squirt. The brake was still binding so I tightened the bleed screw and gently tapped the caliper with a rubber mallet. No difference, the brake is still binding and stopping the wheel from rotating freely.
I'm assuming a new caliper is in order? is there anything I can do with the old caliper to give it a chance of a new life?
Thanks so much. _________________ 1976 VW Transporter, 2.0 FI Engine |
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2744 Location: Hamble, Hampshire, UK
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Posted: Wed Apr 21, 2021 1:15 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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If the caliper is rusted up, then you may have to use more than a rubber hammer to knock the pads sideways out of the caliper (remove the pins first !) . If it is rust, then you can file off the rust from the caliper where the sides of the pad rest against the caliper. The pad should be a loose fit on the pins so it can move.
At that point, buying new pads, fitting them and checking the brakes actually work is a good idea.
I once had a car with a rusted caliper - gentle braking and it would pull hard to the kerb side of the road as the pad stayed put on that side.
Press really hard on the brakes, and it would bend the pads back into contact with the disc, and stop straight.
Some work with a hammer and a file and it had one less bad problem. (also 150 miles to the gallon of engine oil, carpet wrapped round steering column that snapped suddenly causing fish tailing at 70mph , starter ring fell off flywheel daily, carburettor float jammed down in the rust at 100mph .. ... Good old British Leyland 1974 car , rusted through by 1985) _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
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danfromsyr Samba Member
Joined: March 01, 2004 Posts: 15144 Location: Syracuse, NY
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Posted: Wed Apr 21, 2021 4:07 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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yeah you can put it in the box you get the new one in and return it as a core..
that's the best thing you can do for/with it.
Brakes are too important to squabble over $100~150 for a 5~20 year life item.
*I used autozone as a example because it's easiest on core returns.
but go with a favorite VW vender if you prefer.
https://www.autozone.com/brakes-and-traction-control/brake-caliper-front/volkswagen/transporter
wagohn wrote: |
Wildthings wrote: |
Once you have driven 10 miles or so on a road that requires you to use the brakes frequently crawl underneath and loosen the bleeder on the side that is getting hot and see if there is any pressure in the line. A slow seepage of brake fluid is normal, but a pulse of fluid as you first open the bleeder is not. However if the bleeder is all clogged up with rust and dirt, you will not get a good test. |
Update: The bus has sat in the garage for 2 days now and so I jacked up the front. The drivers front brake is still stopping the wheel from rotating freely - even when cold. I then removed the tire and slackened the top bleed screw on the caliper (there are 2 screws, I only slackened the top bleed screw).
The bleed screw began to slowly drip fluid, there was no squirt. The brake was still binding so I tightened the bleed screw and gently tapped the caliper with a rubber mallet. No difference, the brake is still binding and stopping the wheel from rotating freely.
I'm assuming a new caliper is in order? is there anything I can do with the old caliper to give it a chance of a new life?
Thanks so much. |
_________________
Abscate wrote: |
These are the reasons we have words like “wanker” |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Wed Apr 21, 2021 4:12 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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mikedjames wrote: |
If the caliper is rusted up, then you may have to use more than a rubber hammer to knock the pads sideways out of the caliper (remove the pins first !) . If it is rust, then you can file off the rust from the caliper where the sides of the pad rest against the caliper. The pad should be a loose fit on the pins so it can move.
At that point, buying new pads, fitting them and checking the brakes actually work is a good idea.
I once had a car with a rusted caliper - gentle braking and it would pull hard to the kerb side of the road as the pad stayed put on that side.
Press really hard on the brakes, and it would bend the pads back into contact with the disc, and stop straight.
Some work with a hammer and a file and it had one less bad problem. (also 150 miles to the gallon of engine oil, carpet wrapped round steering column that snapped suddenly causing fish tailing at 70mph , starter ring fell off flywheel daily, carburettor float jammed down in the rust at 100mph .. ... Good old British Leyland 1974 car , rusted through by 1985) |
Thanks. I went ahead and took the pads out of the caliper. Quite a chore as they were in there pretty tight. On inspection, it seems the PO had attached the shims to the pads with red rubber sealant material. That material was breaking up and was now packed with brake dust where a gap had appeared between the two surfaces. I used brake cleaner to clean everything up and applied a light sanding to the pads and shims. The forward piston would allow the shim/pad but the rear only the pad. Rather than force things, i decided to leave out the shims and see what happens.
Took the bus for a test drive and no break rub noise, bus stopped well, and zero heat on the wheel on getting home with the wheel spinning freely. Also, the pedal felt more "normal" with a little play in travel before hitting the braking zone. Previously, the pedal seemed to be at the very top and applied braking immediately.
Obviously this is not perfect because those shims should go in there. I'm going to drive carefully (5 mile trips) and see how we go. Hopefully the clearing out of the brake dust/rubber sealant will allow things to loosen up a little over a few miles.
Thanks all.
PS - mikedjames - I drove a 1978 MGB for many years so feel your pain. I'm quite familiar with Lord Lucas. _________________ 1976 VW Transporter, 2.0 FI Engine |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51153 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Wed Apr 21, 2021 4:19 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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While the pads were out did you try prying the pistons back?, did they move freely?, or did one put up a fight?
Maybe it's not hot now because it's stuck and not doing much braking? _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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Last edited by busdaddy on Wed Apr 21, 2021 4:21 pm; edited 1 time in total |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Wed Apr 21, 2021 4:20 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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busdaddy wrote: |
While the pads were out did you try prying the pistons back?, did they move freely?, or did one put up a fight? |
No, I did not. _________________ 1976 VW Transporter, 2.0 FI Engine |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51153 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Wed Apr 21, 2021 4:25 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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Try prying both back into the caliper a 1/4" + , be prepared for the pedal to go to the floor a couple pumps before they reseat themselves after you get it back together, pump the brakes before driving anywhere.
If one (or both) don't move you have a problem. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Wed Apr 21, 2021 4:28 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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busdaddy wrote: |
Try prying both back into the caliper a 1/4" + , be prepared for the pedal to go to the floor a couple pumps before they reseat themselves after you get it back together, pump the brakes before driving anywhere.
If one (or both) don't move you have a problem. |
I will try that. Thanks so much. _________________ 1976 VW Transporter, 2.0 FI Engine |
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wagohn Samba Member
Joined: June 24, 2014 Posts: 740 Location: United States
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Posted: Sun Apr 25, 2021 2:32 pm Post subject: Re: Front Drivers Brake Hot - Thoughts? |
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wagohn wrote: |
busdaddy wrote: |
Try prying both back into the caliper a 1/4" + , be prepared for the pedal to go to the floor a couple pumps before they reseat themselves after you get it back together, pump the brakes before driving anywhere.
If one (or both) don't move you have a problem. |
I will try that. Thanks so much. |
I used a piece of wood to attempt to pry the pistons back a little. There didn't seem to be any more movement backwards but the shims would then fit, so I guess something moved.
Drove the bus around town today and it feels great. Brakes feel good and no heat on the hub when getting home. I just think the caliper needed a heavy cleaning.
Thank you all so much. Have a great day. _________________ 1976 VW Transporter, 2.0 FI Engine |
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