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bruno2601
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Joined: April 29, 2021
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 Posted: Thu Apr 29, 2021 9:25 am Post subject: Type 4 Front Brake Calipers |
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I have a question regarding the front brake calipers if anyone knows the answer.
Are these sided?
I have looked and cannot find any physical difference between left and right BUT the part numbers suggest they are sided.
411 615 107 for left and 411 615 108 for right!
Also where is the part number stamped on the caliper because again I cannot find it as they also come with suffixes B, C, D etc.
Thanking you in advance. |
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Cees Klumper
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Joined: March 13, 2021
Posts: 60
Location: Long Beach, California
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| Posted: Thu Apr 29, 2021 9:58 am Post subject: Re: Type 4 Front Brake Calipers |
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I would guess any difference would be that the brake hose connection and bleed nipple are in different locations on the caliper rather than in the center. Funny thing is, I just rebuilt mine a few weeks ago, but I believe I did them in turn (not at the same time) and I don't recall whether they were identical or not. But that would be my guess: different location of the connections.
The rebuild went fine with standard rebuild kits. Was glad to have compressed air to press out the pistons. It only takes a little pressure, and they still pop out with force, so be careful if you go the rebuild route.
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'71 411 stationwagon |
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bruno2601
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| Posted: Thu Apr 29, 2021 11:01 am Post subject: Re: Type 4 Front Brake Calipers |
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| Cees Klumper wrote: |
I would guess any difference would be that the brake hose connection and bleed nipple are in different locations on the caliper rather than in the center. Funny thing is, I just rebuilt mine a few weeks ago, but I believe I did them in turn (not at the same time) and I don't recall whether they were identical or not. But that would be my guess: different location of the connections.
The rebuild went fine with standard rebuild kits. Was glad to have compressed air to press out the pistons. It only takes a little pressure, and they still pop out with force, so be careful if you go the rebuild route. |
The main reason of asking was that about 3 years ago I replaced the 2 calipers with 2 NOS ones and at the same time I replaced the discs (rotors). Since then they have squealed when steering to the left (not braking) then for so long after straightening up. The master cylinder had a leak so that was reconditioned. I replaced the brake pipes and the flexible pipes and the brake pads. I fact, everything I could think of and still it squeals!!
It was after looking in the parts list a few days ago when I noticed the part numbers, hence my question as to whether they are sided. As I say, I cannot find a difference on the outside so wondered if the channeling for the fluid inside is different to cause this problem (I don't know how it would though).
So... have I got 2 left calipers fitted or 2 right ones or doesn't it make any difference? I cannot check as they do not have part numbers stamped on them as mentioned earlier, or at least I cant find them.
I wouldn't have thought it was a sticking piston because its not after I brake, it when I steer mainly to the left as if that it forcing fluid to one of the calipers.
So, I'm a bit at a loss of what the problem is. |
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MarcVoss
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Joined: July 21, 2019
Posts: 67
Location: DE, Munich
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| Posted: Thu Apr 29, 2021 11:28 am Post subject: Re: Type 4 Front Brake Calipers |
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The first version of the calipers had only one nipple, the nippel must be on top, and this is the only difference. Later versions with letters after the partnumber had two nipples, so they can be used on both sides. I guess, the nipples have different diameter, but this will not really matter the function.
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Best Regards from Germany, the origin country of Volkswagen.
Marc |
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bruno2601
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| Posted: Thu Apr 29, 2021 11:52 am Post subject: Re: Type 4 Front Brake Calipers |
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| MarcVoss wrote: |
The first version of the calipers had only one nipple, the nippel must be on top, and this is the only difference. Later versions with letters after the partnumber had two nipples, so they can be used on both sides. I guess, the nipples have different diameter, but this will not really matter the function.
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Mine definitely have the 2 nipples on each cylinder, so that should be the issue then really. |
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raygreenwood
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Joined: November 24, 2008
Posts: 21518
Location: Oklahoma City
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| Posted: Thu Apr 29, 2021 12:15 pm Post subject: Re: Type 4 Front Brake Calipers |
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Yes...MarVoss is spot on.
One other issue to look at. You note that the brakes squealed on one side only when you turn.
A couple of items that can cause this:
1. You note that these calipers were NOS. Generally....NOS CALIPERS are not a problem. However...NOS brake master cylinders and rear wheel cylinders that are over about 7 years old....are a problem as the seals in them harden up in position and cannot properly expand to seal.
This is because the seal type inside of the caliper is totally different. It has no lips. It is a square profile ring that simply gets squeezed and distorted to work. Also the EPDM rubber is overall very uniform and long life. It does not really shrink but does get stiffer with age.
HOWEVER....the OUTER boot...is a different material. It has to put up with high heat and solvents/oils. It is usually viton.
With age...the boot can be causing some drag on retraction of the piston when you let pressure off. So...coupled with the next problem below....it can cause a squeal when it contacts the rotor.
2. I am betting from the part 3's....that you have a pre-august of 1972 VW 411?
So the pre-August 1972 411....had the un-strengthened rotor. They did not have the raised ring around teh center. People think this ring is to make it more convenient to put teh wheel on. It is not for that. It strengthens the rotor and prevents flexing while turning....which can cause the exact problem you are having. The rotor would flex out of line and rub against the pads.
The early calipers had a feature inside that was a pin and clutch that was designed to keep the pistons from cocking in the bore when the rotor flex heavily.
The problem usually only happened when you were turning AND you had considerable weight in the car or were moving at speed. If this happens at low speed to...you possibly have a caliper piston that is not retracting fully.
NOTE: this an also happen is you have some air bubbles in the caliper or that end of the line.
Or....if a brake hose is starting to swell inside an is not letting pressure fully drop off.
3. If one rotor has excessive free play in the wheel bearings...you can get this squeal as well when turning....but again...its usually coupled with a piston not retracting fully.
Ray |
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bruno2601
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| Posted: Thu Apr 29, 2021 12:31 pm Post subject: Re: Type 4 Front Brake Calipers |
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Thanks for that Ray..... mine is actually a 1973 412.... it has got this strengthening ring, I did not know it was for that!
I have adjusted the bearings too, as I thought the same.
Maybe it is a piston not fully retracting.
The flexible pipes felt hard so I changed them too. I cut the old ones and saw that the internal bores were different.... so I thought that that had to be the problem. Got new ones on..... exactly the same!!
So looking at it can only come down to the calipers... cant it? |
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Cees Klumper
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Joined: March 13, 2021
Posts: 60
Location: Long Beach, California
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| Posted: Thu Apr 29, 2021 12:56 pm Post subject: Re: Type 4 Front Brake Calipers |
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Sorry if I missed it, but have you put some anti-squeal grease behind the pads, and do you have the stainless steel plates between the calipers and pads? Those are specifically to prevent squealing.
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'71 411 stationwagon |
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raygreenwood
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Joined: November 24, 2008
Posts: 21518
Location: Oklahoma City
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| Posted: Thu Apr 29, 2021 2:42 pm Post subject: Re: Type 4 Front Brake Calipers |
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| Cees Klumper wrote: |
| Sorry if I missed it, but have you put some anti-squeal grease behind the pads, and do you have the stainless steel plates between the calipers and pads? Those are specifically to prevent squealing. |
Very good point.....but do not use the anti squeel "greases". Those are really only for sliding caliper friction points. It is a risk in hard braking that it will run.
Use a good anti-squeel compound. These are usually a mixed high temp ceramic and RTV. They are a flexible adhesive that dqkp rotational pad vibration. That....and order a set of Raybestos pad shims.
I thought you might have an,earlier car because you were just listing the basic part numbers. There are actually four different letter code calipers for each part number in the parts book.
Ray |
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bruno2601
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| Posted: Thu Apr 29, 2021 2:51 pm Post subject: Re: Type 4 Front Brake Calipers |
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| Cees Klumper wrote: |
| Sorry if I missed it, but have you put some anti-squeal grease behind the pads, and do you have the stainless steel plates between the calipers and pads? Those are specifically to prevent squealing. |
Well, they were on, but they seemed to make it worse, so they were taken off! |
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raygreenwood
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Joined: November 24, 2008
Posts: 21518
Location: Oklahoma City
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| Posted: Thu Apr 29, 2021 7:05 pm Post subject: Re: Type 4 Front Brake Calipers |
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| bruno2601 wrote: |
| Cees Klumper wrote: |
| Sorry if I missed it, but have you put some anti-squeal grease behind the pads, and do you have the stainless steel plates between the calipers and pads? Those are specifically to prevent squealing. |
Well, they were on, but they seemed to make it worse, so they were taken off! |
Yes....that tells you something.
So lets be sure we are speaking of the same thing.
1. Are we speaking of "anti-rattle/squeal" shims?
Those would be part numbers like
Raybestos DS8003
Carlson 18003
Wagner SH12085
The Raybestos appears to be obsolete. Cannot find them anymore.
Here are the Carlson ones...may also be obsolete
https://www.rockauto.com/fr/moreinfo.php?pk=5227593&cc=1209293
Cant find the Wagner either 
BUT...I did find these:
https://www.fcpeuro.com/products/bmw-audi-mercedes...d-shim-set
Check this out.
Here is the pad design and dimensions of our front pads from a Centric part # for our cars in Rockauto
Here is the pad dimension of the rear brake pad for a 1980 Mercedes 300SD
Same basic caliper and pad....and if you scroll down in that FCP Euro link...those stainless shims fit a 1980 Mercedes 300SD rear...so will fit our fronts!
And...at $1.04 each for pad shims for our car...stainless no less....that rocks!
2. or...are you speaking of the half moon cut out shims that fit within the caliper piston and over one bot? Those are anti-rotation shims...and also allow a dipped edge on the inner edge of the brake pad....a pressure relief. They also as noted keep the piston from rotating which tears up the outer boot.
The pad BACKING shims listed above in #1.....make up some thickness placing the pads closer to teh rotor...so if one piston is sticking slightly...and you get a little bearing or disc flex...it can drag and squeal when you turn.
Ray |
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bruno2601
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| Posted: Fri Apr 30, 2021 12:35 am Post subject: Re: Type 4 Front Brake Calipers |
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Ray, it was the anti rotation ones that were fitted and these seemed to make the problem worse.... it did improve when these were removed but it is still there.
It is definitely a squeal noise but not a continuous squeal it is on and off with the speed of the wheel rotation then fades away which yes could point to a warped brake disc but on normal braking I cannot feel it in the pedal (which I would expect).
I'm not convinced its a piston slow at retracting back or sticking because normal braking doesn't cause the problem
You did suggest that it could be disc flexing, if that is the problem how can I remedy this? or can it be?
It has to be either the disc(s) or the caliper(s) as the problem only started when these were changed. Although, as I said previously, everything else to do with the braking as been changed at the front end. |
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raygreenwood
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Location: Oklahoma City
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| Posted: Sat May 01, 2021 6:54 am Post subject: Re: Type 4 Front Brake Calipers |
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| bruno2601 wrote: |
Ray, it was the anti rotation ones that were fitted and these seemed to make the problem worse.... it did improve when these were removed but it is still there.
It is definitely a squeal noise but not a continuous squeal it is on and off with the speed of the wheel rotation then fades away which yes could point to a warped brake disc but on normal braking I cannot feel it in the pedal (which I would expect).
I'm not convinced its a piston slow at retracting back or sticking because normal braking doesn't cause the problem
You did suggest that it could be disc flexing, if that is the problem how can I remedy this? or can it be?
It has to be either the disc(s) or the caliper(s) as the problem only started when these were changed. Although, as I said previously, everything else to do with the braking as been changed at the front end. |
Yes.....but it still could be a piston not backing off. Why do I say this?
Because.....there are no such thing as 100% straight rotors. This is why the books list a tolerance for radial and axial runnout for rotors. Same for wheel bearing play (more on that in a minute).
Your rotors may only be off....either radially or out of plane from center to edge (helicoptering) by a thousandth or two......but if a piston is not retracting fully....its to close and they WILL hit the high spots on the rotor.
The windage or pad gap.....is only about 0.004" at best adjusyyment....but can get out to about 0.010"
Meaning.....when the pads retract after you let off the brake.....they only back off from contact.... by around 0.004". A little more disc runnout than normal.....or a rough or nog pully pressed in bearing.....and one piston not backing off can cause your problem.
Yes.....the anti rotation plates are important. Should not leave those out.
Ok.....what brand of rotors are these?
What brand of wheel bearings?
What brand of pads?
If you are leaving the anti rotation plates out.....you should be having MORE issues because the plates missing will allow the pads to eventually wear oddly.
Just a question....when you are adjusting wheel bearing freeplay.....how are you doing this and are you measuring freeplay and runnout? Ray |
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bruno2601
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| Posted: Sat May 01, 2021 8:38 am Post subject: Re: Type 4 Front Brake Calipers |
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Hi Ray,
Thanks for all that info, it does make sense, especially the wheel bearing if the outer race isn't perfectly home. I can see where it could cause the issue. so maybe it would be with getting a dial indictor to check this out to see if the rotor in within the specification?
The rotors where bought from a guy in the US off Samba as genuine NOS items.
The bearings I dont know the make and the pads are I think Mintex but again not 100%.
When checking wheel bearing play I just do it be feel and tighten and loosen as required. Probably not the right thing to do. |
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raygreenwood
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Joined: November 24, 2008
Posts: 21518
Location: Oklahoma City
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| Posted: Sat May 01, 2021 11:45 am Post subject: Re: Type 4 Front Brake Calipers |
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| bruno2601 wrote: |
Hi Ray,
Thanks for all that info, it does make sense, especially the wheel bearing if the outer race isn't perfectly home. I can see where it could cause the issue. so maybe it would be with getting a dial indictor to check this out to see if the rotor in within the specification?
The rotors where bought from a guy in the US off Samba as genuine NOS items.
The bearings I dont know the make and the pads are I think Mintex but again not 100%.
When checking wheel bearing play I just do it be feel and tighten and loosen as required. Probably not the right thing to do. |
The method you are using for adjusting bearing freeplay is fine.....but you do have to measure actual runout. For ages I just did it by feel and got away with it.....until one year I put in a poor set of bearings and they could not produce a good axial play even with proper drag setting.
It could be either the inner or outer race nice fully pressed in. It could also be.....a bent axle.....rare.....and also probably not it.
The fact that you only have this problem when turning.....tells me that either something is moving when you turn.....either bearing slack or rotor flex.....and its either enough to cause squeel by itself.....or its coupled with slightly less pad to rotor free play on one piston or another.
One thing to try.....drive it until the brakes are warmed up.....bring it home and jack the dront end up and remove both wheels. Turn each rotor by hand and see if you have drag differences. Ray |
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bruno2601
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| Posted: Sun May 02, 2021 11:39 am Post subject: Re: Type 4 Front Brake Calipers |
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Hi Ray
Thanks for all the advice. I'll definitely try what what you said about getting the rotors hot and checking them.
I'll let you know how I get on with everything you've suggested.
Got a hot start problem to sort out first though and an intermittent starter problem too.
Thanks again |
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