Brake pads

[overherebc]

I'll try to explain the background first.

Bought replacement front discs for the front of my rather old car

( 42 years old ) They are a bit thicker than the originals and the new pads just don't fit.

I dont really want to start stripping the discs off and getting them machined.

Question.

Considering that pads are high friction material would machining the pads by say 2mm be feasable or even possible? It would still leave about 13mm of friction material.

Edit.

Rear/front pads are not interchangeable. Different shape and size as rear is a combination disc and drum system.

Edited December 31, 2020 by overherebc

[overherebc]

Combo disc drum if you haven't seen one.

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[soi3eddie]

 

Sounds to me as if they have supplied you the wrong discs for your car. Sometimes specifications change on different year models. Did you buy from a main dealer or a generic spares shop?

 

[stubuzz]

Put a piece of 80 grit paper on a flat surface and rub the pads on it until they are the correct thickness. Try to do both sides evenly.

[Crossy]

Dumb question, you have ensured that the caliper pistons have gone into the housing as far as possible, they are sometimes very tight.

 

Nothing to stop you wearing down the new pads mind, do you know anyone with a belt-sander?

[overherebc]

1 hour ago, Crossy said:

Dumb question, you have ensured that the caliper pistons have gone into the housing as far as possible, they are sometimes very tight.

 

Nothing to stop you wearing down the new pads mind, do you know anyone with a belt-sander?

Belt sander was a thought I had.

Original discs for the car are almost impossible to get. Only available from overseas at an arm and a leg.

I'll go for belt sander and a big dose of patience I reckon.

[Crossy]

In the past I've had to use a G-clamp to push the piston(s) back enough to get new pads in.

 

A final thought, are the calipers of the single-piston type with one actual moving piston and the whole carrier sliding to move the other pad? I've had these slidy bits seize and give a similar symptom.

 

What car is it? Could you post some shots of the calipers?

 

If you go for the belt sander please wear a decent mask, pads don't have asbestos now but the dust still isn't good for you.

 

 

 

[PGSan]

2 hours ago, overherebc said:

42 years old 

The car?  Or you?

[canthai55]

37 minutes ago, Crossy said:

A final thought, are the calipers of the single-piston type with one actual moving piston and the whole carrier sliding to move the other pad? I've had these slidy bits seize and give a similar symptom.

I always use Never Seez on caliper pins. won't wash out and keeps them from seizing.

Partial to the copper blend - Kopr Kote another good brand

[overherebc]

1 hour ago, Crossy said:

In the past I've had to use a G-clamp to push the piston(s) back enough to get new pads in.

 

A final thought, are the calipers of the single-piston type with one actual moving piston and the whole carrier sliding to move the other pad? I've had these slidy bits seize and give a similar symptom.

 

What car is it? Could you post some shots of the calipers?

 

If you go for the belt sander please wear a decent mask, pads don't have asbestos now but the dust still isn't good for you.

 

 

 

Two pistons system. 

One of the other forums I joined is specific to the car and it seems to be a common problem generally cured by skimming 2mm off the ventilated disc but considering the low mileage the car will do and I didn't know that I am just thinking about another way. Taking the discs back off, removing the bearings etc ( dont need swarf getting into them etc ) 

Just asking about skimming the pads to maybe make it easier and quicker.

[liddelljohn]

wear  a safety mask and dont breath in the particles when  shaving the pads

[overherebc]

19 minutes ago, liddelljohn said:

wear  a safety mask and dont breath in the particles when  shaving the pads

Little workshop nearby I trust can do it. I'll let them do the skimming.

Might even get the two callipers recond'

Edited December 31, 2020 by overherebc

[mistral53]

2 hours ago, overherebc said:

Belt sander was a thought I had.

Original discs for the car are almost impossible to get. Only available from overseas at an arm and a leg.

I'll go for belt sander and a big dose of patience I reckon.

Wont work - at least not as a manual fly-by-your-pants job - however low tech brakes seem to look, there is quite a bit more accuracy required for what you intend to do. To wit, if your pads differ in thickness in/out or top/bottom, they will either jam, bend or not retract, and most certainly leave you with a fraction of the stopping power designed for. Brakes are a safety item, don't risk it.

[overherebc]

28 minutes ago, mistral53 said:

Wont work - at least not as a manual fly-by-your-pants job - however low tech brakes seem to look, there is quite a bit more accuracy required for what you intend to do. To wit, if your pads differ in thickness in/out or top/bottom, they will either jam, bend or not retract, and most certainly leave you with a fraction of the stopping power designed for. Brakes are a safety item, don't risk it.

This is a very old car and won't be driven around as a daily runner. I doubt it will ever see more than 80/90kph.

15th of may next year it will celebrate its 46th birthday.

From manufacturers records it's the only right hand drive of its type imported new and tax paid into Thailand in 1975. I've only seen one other and it was a  LHD hooky import from USA.

Edited December 31, 2020 by overherebc

[katana]

I had that problem on some new motorcycle pads that were slightly too big for whatever reason. The shop ground them down a bit and they worked fine when fitted.

[transam]

You can get the discs skimmed at a machine shop...

[steve187]

16 minutes ago, transam said:

You can get the discs skimmed at a machine shop...

i asked at a local shop to me 1,100thb each disc

[transam]

3 minutes ago, steve187 said:

i asked at a local shop to me 1,100thb each disc

Sounds OK.....

[VocalNeal]

Eventually, even if correct, the pads would wear down to 13mm. So I see no problem sanding then down and starting at 13mm, if needs be.

[transam]

1 minute ago, VocalNeal said:

Eventually, even if correct, the pads would wear down to 13mm. So I see no problem sanding then down and starting at 13mm, if needs be.

The problem with sanding is getting a 100% flat parallel surface, skimming the disc (if enough material is present) is the way to go, I have the T-shirt for both methods..

[Yellowtail]

If the pads are too thick, how did you get them on?

 

And assuming they are on, how is it they are too thick? 

[PFMills]

3 hours ago, Yellowtail said:

If the pads are too thick, how did you get them on?

 

And assuming they are on, how is it they are too thick? 

I think you have just become the Einstein  of Thaivisa.

[canthai55]

OP - no need to worry. Sand the pads down so they fit.

It does not need to be 100% flat - you ain't building a piano. A few hard applications from 100 kph will soon have them flat and true to the rotors.

Comments here about pads jamming, wheels locking up, etc etc just a bunch of hogwash.

 

 

[transam]

15 hours ago, canthai55 said:

OP - no need to worry. Sand the pads down so they fit.

It does not need to be 100% flat - you ain't building a piano. A few hard applications from 100 kph will soon have them flat and true to the rotors.

Comments here about pads jamming, wheels locking up, etc etc just a bunch of hogwash.

 

 

Do not follow this advice if you want to do the job properly...????

 

OP, I upgraded the brakes on my fun car, replacing the single pot calipers with 4 pot Wilwood conversion, which included all alloy rotating mass hardware. Fitted it all to find the brakes were not much better. ☹️

 

So, I decided to install larger diameter discs. The brake shop I used fabricated anything for a brake upgrade in house.

Gave them all my stuff, so they could find a disc that could be used. They found a Jag disc that would do the job except they would have to machine up new alloy bell's for the disc to bolt onto, which they did.

 

The last hurdle was the discs were a little wider than the Wilwood vented discs, you guessed it, they skimmed the disc sides to the exact size of the Wilwood's so the pads would fit, and future pads would fit.....Job done...????

 

 

 

[canthai55]

1 hour ago, transam said:

Do not follow this advice if you want to do the job properly

And this has what to do with a 42 year old car exactly - describing something you did in the dim mists of time to a car you can't stop talking about on most every topic posted in this forum

[transam]

9 minutes ago, canthai55 said:

And this has what to do with a 42 year old car exactly - describing something you did in the dim mists of time to a car you can't stop talking about on most every topic posted in this forum

My fun car is now 44 years old, if it's still out there.....????

 

But, doesn't matter how old the car is or what the car is, disc brakes are virtually all the same in operation, your fix is a cowboy fix. If you don't like my input, well I am sorry, but it is something to read that may be of interest to others.....????

[Adiudon]

Angle grinder, vice and a face mask,, one pass of the grinder and measure, do them all the same number of passes, job done. Grind the lip off the disc if there is one too.

Fit the pads and drive around the block a few times braking light at first to rub off the high points, won't take long to bed them in.

No problem what so ever, done it myself on brake pads and shoes on bikes, cars, trucks and buses never had a problem'. 

[canthai55]

1 hour ago, transam said:

your fix is a cowboy fix.

So - grind a little off the pads is a 'Cowboy Fix' ???

555

[canthai55]

If it is a F1 car - then maybe not a good idea.

Or a Ferrari - or a Bugatti, or a ...

But a daily driver, run-of-the-mill car - like a bloated Trans Am or a Vigo or a

Swift ...

Makes not a bit of difference

[Yellowtail]

I'm still trying to figure out how he can do anything without taking the pads off. 

 

Maybe put lapping compound on the disks and drive around riding the brake? 

 

If the surface of the pads are not flat and parallel  to the piston they will side-load the seals in the calipers.

 

I can only imagine how long it would take to take 2mm off of four pads with a piece of sandpaper, my arm hurts just thinking about it...