Brake problems

[Chino]

Had some fun and games with the front brakes whilst out driving today, posted all info in my progress:

viewtopic.php?f=4&t=9022&p=57142#p57142

If anyone could advise I'd be most grateful

[937carrera]

Repost into this thread

Sounds like the caliper was seized with resulting generation of heat. That heat cause the smoking, which was a visible sign of heat in the caliper itself, which transmitted into the fluid and allowed some of it to boil (i.e change to a gas). Gases are compressible, hence when you pressed on the pedal it caused no movement. Brake fluid is hydroscopic so old fluid absorbs water and boils at a lower temperature. Pumping the brake pedal does bring back the pedal.

If it was me I would do this

1. Check that the brake system is hydraulicaly sound with no leaks. Press firmly on the pedal until there is no movement and see if it moves to the floor. If it does then either you have a leak (pipe / slave cylinder) or a master cylinder problem.
2. Assuming all is OK, I would then free off the caliper, clean off any contamination on the disc and unless you know how fresh the brake fluid is, do a fluid change. If you are going to do that and the flexis are in poor replace those as part of the process.

[Editor]

See your project thread. Has the pedal cluster been out recently? Some people think you can adjust the brake free-play by changing the pushrod length - you MUST NOT CHANGE THAT LENGTH!

[Chino]

Many thanks guys, have posted in there, but will in here too for completion.

I will look to change pads, flexis and fluid as a minimum, discs depending on condition. Are there any brands/suppliers I should be looking at in particular? I may as well fit the best parts I can get hold of/afford.

[937carrera]

Will, I'm sure you got a fright and are taking the view that you want to replace everything "to be safe". It's entirely up to you of course, but it the problem was just a sticking caliper, then there is really no need to replace disks & pads etc.

If it makes you feel better, when I recommissioned my 412 I had sticking calipers. I simply eased them free and cleaned the discs up to an acceptable condition. After a few miles everything was bedded in fine. I was reminded in the process that in the old days (well my younger days at least), replacing discs was not a normal service job - especially as on a type 4 that also means replacing the front wheel bearings which is not necessarilly a trivial task. Not sure if that also applies to the type 3.

Anyway, entirely your choice what you do. As to manufacturers, I would choose branded, eg ATE, Pagid discs. Cheaper ones are available, but they tend to warp more easily. Of course I don't know what is actually available for the type 3, so hopefully those with greater knowledge will be along soon.

[Chino]

Thanks David

On closer inspection it seems the pads are quite worn, Chris who has had a quick look today reckons the Pistons were extended quite far as a result and got stuck. It's having new pads and fluid tomorrow but he reckons the disc is ok. We are hoping the caliper winds back in ok but will deal with that if necessary

[937carrera]

Oh, that's cheating. When I did the 412 I had nothing but large screwdrivers and a pry bar.

Since then I had to buy a wind back tool to do the rears on a Polo GTi because of the thread on the piston. So much easier with the right gear.

Sounds like pads and fluid is the right approach, if the bleed nipples aren't a pain you'll be back on the road tomorrow

[Chino]

Fingers crossed David, hopefully the calipers won't give us any trouble. we will cross that bridge when we come to it if needbe

[Chino]

To update, Chris has inspected my calipers off the car today and tells me they are in a terrible way and would always leak and cause issues in their condition. He has ordered me some ATE replacements. I imagine these will be Beetle parts, but from what he tells me of the state of the existing units it sounds like they will be more effective. I will collect the old parts with a view to keeping for potential professional refurbishment(depending how far gone they are) as I believe Type 3 calipers have more braking force than beetle ones?

[937carrera]

This thread might be useful http://www.thesamba.com/vw/forum/viewtopic.php?t=142569

I wouldn't be a fan of having Beetle calipers in a type 3, even if they fit, check what you are getting especially as I suspect they won't be cheap

[Chino]

I'll be honest David, I'm going on an assumption they are a bug or Ghia caliper here, as i don't think anyone makes type 3 now? I should double check this. Chris did actually say he could rebuild mine but they were so far gone they would no doubt leak and possibly seize again, hence fitting new replacements for now to get the car on the road whilst I look into a thorough refurbishing service. If anyone can recommend companies for this is be most appreciative. The price is not too bad for these in fairness, but I am regarding them as a 'stop gap' measure to get me motoring.

[937carrera]

http://www.machine7.com/section.php?xSec=709

Looks like you need to know exactly what year your car is a '71 is the crossover year between calipers types. Later type 3 / type 4 calipers do seem to be available but only one side in stock. You might be lucky

[Chino]

http://www.machine7.com/section.php?xSec=709

Looks like you need to know exactly what year your car is a '71 is the crossover year between calipers types. Later type 3 / type 4 calipers do seem to be available but only one side in stock. You might be lucky

Thanks, my car was a May '71 model...hmmm best get measuring between the bolt holes I guess!

[miketyp3]

May 71 will be the earlier ones.
I have Beetle calipers on both my disc brake cars (nothing else being available at the time) and they work fine.
I think the beetle is a 40mm piston and the Type 3 would be 42mm. I'm not saying there's no difference, but if there is I have not noticed it.

[Chino]

May 71 will be the earlier ones.
I have Beetle calipers on both my disc brake cars (nothing else being available at the time) and they work fine.
I think the beetle is a 40mm piston and the Type 3 would be 42mm. I'm not saying there's no difference, but if there is I have not noticed it.

Thanks Mike, that reassures me somewhat. I imagine new, working Beetle calipers will be better than what I'm used to anyway, from the sounds of it mine were way past their best. I'll rescue my old calipers from the scrap pile and they can go in my shed in case I ever decide I want to investigate having them refurbished.

[937carrera]

As posted in the Samba thread I linked to, the 2mm smaller diameter Beetle ones have about 10% less effective force that proper type 3 calipers. That's engineering, but of course smaller good ones will be better than larger knackered ones.

I found this site earlier this morning if you want to have them rebuilt. I suggest you ask your mechanic to put an airline on the caliper to pop the old piston out so you can see the condition of the bore. (it's just an easy way to remove it). Only in Rochdale so easy for you to pop over.

http://brakeparts.co.uk/#!/shop/VW/VARI ... 0cylinders

[Chino]

Thanks David

Here's a little taste of what the old ones look like:

[937carrera]

They look a bit grungy and the dust seals are shot, but it's the internals that are important. I'd certainly try and get them refurbed, they should come back newly anodized

[In2Rust]

I found some NOS boxed genuine VW ATE calipers with the pads whilst on a recent trip to Germany in an old parts warehouse. These are for late Type 3 (and Type 4 so Iam told).

Doesnt get any better than this, why spend money on remanufactured ones when you can have these and like new factory spec braking.

They are in the for sale section at £250 the pair boxed.

[Lint]

Does anyone know what the correct length the push rod should be set at?

[mjrpoulton]

In the VW manual I have for the late 60's there is no dimension, just a template to use to set the pushrod length in situ, following the change from single to dual circuit systems.

[JSR-69]

The absolute length isn't important. You need to set 1mm or so free play so that the master cylinder is not preloaded at rest.

Judi R

[Lint]

In the VW manual I have for the late 60's there is no dimension, just a template to use to set the pushrod length in situ, following the change from single to dual circuit systems.

Would you be able to send me a copy of the template?

[Editor]

The push-rod length for dual circuit can vary a bit, depending on the body geometry, but in practice it rarely differs much. The factory manual says 149.5mm, measured from the tip of the end that goes into the master cylinder to the centre of the pivot hole. The reason it shouldn't be altered from the factory set length is that the body position on the floorpan can have a few mm tolerance. If the pushrod is not the correct length, it can result in the brakes applying themselves as pressure builds, or if brake failure occurs in one circuit not allowing enough pedal movement to apply the other circuit. Dual circuit (tandem) Type 3 brakes are split front/rear.

I'll have to check my spare ones and see if that agrees with them. You adjust the freeplay with the pedal stop-plate, not the pushrod length.

The length is given in section B8 page 4 of the factory Type 3 manual Part 1 which deals with the tandem m/c.

Just checked a spare one and it does measure 149.5mm to the centre of the pivot hole (as close as I can manage judging the tape by eye).

The template mentioned is used from the bulkhead to the pedal assembly. It's not really needed unless there's been a major impact or repairs which may have distorted things. Just ensure the pushrod is the right length and the freeplay on the pedal is about 6-7mm which is equivalent to about 1mm at the pushrod before it touches the rear piston. I just push the pedal manually and feel for a slight movement before contact is made. Loosen the pedal stop plate on the floor to allow adjustment and tighten after.