Spongey brakes Aircooled

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Mjhayes
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Spongey brakes Aircooled

Post by Mjhayes »

My 1982 Aircooled brakes feel very spongey require a lot of pressure to stop/slow down.

Is that normal - I know they’re not modern but I didn’t expect it to be as spongey - also the handbrake isn’t great - looks like new components all round hence my surprise Image
1982 2.0 air cooled single Webber carb 4 speed gearbox

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Mocki
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Re: Spongey brakes Aircooled

Post by Mocki »

No matter the age the brakes should not be “spongey”
Hand brake is possibly over adjusted , so next to no movement , or under adjusted , too much movement
Bleeding the brakes , replacing the fluid ect
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Rosie n' Jim
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Re: Spongey brakes Aircooled

Post by Rosie n' Jim »

As with most vehicles of their era, the self adjusting rear brakes don't! And hand brake adjustment is important too. Order of work is to back off the hand brake, adjust the self adjuster through the hole in the backplate, then adjust the hand brake. This made a huge improvement on my van.
1982 Holdsworth poptop. 2L CU Aircooled.
1982 Danbury tintop Caravelle. 2L CU Aircooled.

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Re: Spongey brakes Aircooled

Post by mshaw1980 »

Yeah when I changed rear wheel cylinders, shoes and drums I bled the rear cylinders with a pressure bleeder at 12psi, adjusted the new shoes so the rear drums were dragging (using a bar to turn the drum on the rear studs), got in the van and applied the brakes several times and held for 10 seconds or so, reconnected the handbrake cable at the shoes and adjust the length of the threaded bar, applied handbrake several times and with it on press brakes again. Release brakes and then out for a test drive. My van now holds nicely on steep hills and the brakes feel great.
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Re: Spongey brakes Aircooled

Post by Simon Baxter »

Rosie n' Jim wrote: 09 Feb 2023, 07:04 As with most vehicles of their era, the self adjusting rear brakes don't! And hand brake adjustment is important too. Order of work is to back off the hand brake, adjust the self adjuster through the hole in the backplate, then adjust the hand brake. This made a huge improvement on my van.

This.
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Re: Spongey brakes Aircooled

Post by Simon Baxter »

mshaw1980 wrote: 09 Feb 2023, 08:51 Yeah when I changed rear wheel cylinders, shoes and drums I bled the rear cylinders with a pressure bleeder at 12psi, adjusted the new shoes so the rear drums were dragging (using a bar to turn the drum on the rear studs), got in the van and applied the brakes several times and held for 10 seconds or so, reconnected the handbrake cable at the shoes and adjust the length of the threaded bar, applied handbrake several times and with it on press brakes again. Release brakes and then out for a test drive. My van now holds nicely on steep hills and the brakes feel great.
And this.
'86 VW T3 syncro panel
'89 VW T3 Westy Atlantic
'81 Porsche 924
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Re: Spongey brakes Aircooled

Post by Simon Baxter »

Please also see the orientation of the brake adjust bar and how it connects to the brake shoe with the hand brake lever.
https://www.youtube.com/watch?v=0i4cKXA3Bm0

We often saw these on 180° out and usually done by folks that should know better.
Mess that up and you'll end up with a poor handbrake, it only goes one way.

Also, you need to fit the upper brake shoe retaining springs the correct way, the ones that clip on to the back plate in the centre.
if you get them wrong then it impedes the brake adjuster and effectivly locks it solid meaning you can't adjust through the hole in the backplate properly. The hook part points upward with the long wire section toward the bottom, this leaves room for the adjuster star wheel to turn.
 
'86 VW T3 syncro panel
'89 VW T3 Westy Atlantic
'81 Porsche 924
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Re: Spongey brakes Aircooled

Post by Simon Baxter »

Also, I try and avoid bleeding brakes by pressing the pedal, I simply gravity blead brakes with very little issue.
Trouble can be that the piston(s) in the master cylinder, in normal operation only use a small portion of the master cylinder bore and that keeps them clean.
You open a bleed nipple and press the brakes it's going to go to the floor and it's going to push those once happy internal master cylinder  seals over the rough part of the master cylinder bore that's full of gunk and possibly corrosion.
Seal can end up torn, damaged or turned and after that that you'll never get a decent pedal feel.
This is one of the reasons why it's so important to keep up with brake fluid changes (every 2 years if you can) as brakefluid by it's very nature readily attracts water from the atmoshere not only lowering it's boiling point and increasing the chance of fluid fade (where the brake fuid can boil and create air bubbles, you can compress a gas but you can't compress a fluid) but also introducing water into a system that's pretty much made of steel or iron leading to internal corrosion.
Old cars, gravity bleed, simply use a length of clear PVC tube (which will discolour and harden in time with contact with brake fluid) into an old clear drinks bottle.
If you struggle to get it flowing then a jiggle of the pedal may get things moving, especially if you've greased brake unions and the pipes are blocked with copper slip but deffo not a full stoke of the pedal.
 
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'89 VW T3 Westy Atlantic
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mioba
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Re: Spongey brakes Aircooled

Post by mioba »

Ahhhhh a lovely job the rear brakes and adjusting the handbrake. Best done on a nice warm day. very rewarding job.

I have done almost everything on my bus since last summer (spent a fortune with Brickwerks).

There is a fantastic video by endfloat on youtube. watch it 10 times and have it on play while doing the job.

But he does fit the springs wrong way round which he mentions in the description (when doing shoes).

Its time consuming as you have to get drag, adjust the star, so on yet very logical.

Done once and done right you will be over the moon.

My handbrake is rock solid on 2 clicks.
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Mjhayes
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Re: Spongey brakes Aircooled

Post by Mjhayes »

Think my handbrake needs replacing - there are no ‘clicks’
1982 2.0 air cooled single Webber carb 4 speed gearbox

Rosie n' Jim
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Re: Spongey brakes Aircooled

Post by Rosie n' Jim »

There will be clicks when the rear brakes are adjusted correctly. 
1982 Holdsworth poptop. 2L CU Aircooled.
1982 Danbury tintop Caravelle. 2L CU Aircooled.

Mjhayes
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Re: Spongey brakes Aircooled

Post by Mjhayes »

ok so it turns out the handbrake isn't finished but its a bit out of shape/worn, i can literally wiggle it side to side so essential the teeth on ratchet are not engaging. If i get the right angle they click and it holds. i think ill invest in a new part. 

it still comes up a bit of a way to be fair and my brakes still need attention i cant believe they are adjusted right. 

thanks 
1982 2.0 air cooled single Webber carb 4 speed gearbox

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