Brakes advice please
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
I ended up balling up a load of '0000' wire wool around a bobbin, soaked in WD40, chucked up in my drill and gave them a thorough cycle, which has brought them up glass smooth with almost a reflective surface like a well worn engine block cylinder - more than good enough and the rebuild kit will be here by the weekend, so all should be well.
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
My rebuild kit arrived today so I finished off refining the finish on the bores and probably got carried away with the therapeutic nature of the process, but nonetheless, here are the results....
Got everything reassembled and the system bled, ready for road test tomorrow if the weather is kind.
I shall report the outcome.
Got everything reassembled and the system bled, ready for road test tomorrow if the weather is kind.
I shall report the outcome.
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
Just to bring this thread to hopefully a close, got the calliper refitted, system bled, new pads both sides and took for a drive - it's like a different car.
Firm pedal, stops straight as a die and just feels so much more stable and planted under braking.
I'm really please, thanks everyone for your input, help and advice.
Firm pedal, stops straight as a die and just feels so much more stable and planted under braking.
I'm really please, thanks everyone for your input, help and advice.
Safety Car
Joined: Jul 2005
Posts: 3,691
Likes: 833
From: WI
Glad you got it working! 
When the car sits for periods, like over the winter, go out and press the pedal hard a couple times ...every 3 weeks or so. That'll keep the lip seals from 'sticking' to the sides of their bores (and last a lot longer).
When the car sits for periods, like over the winter, go out and press the pedal hard a couple times ...every 3 weeks or so. That'll keep the lip seals from 'sticking' to the sides of their bores (and last a lot longer).
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,035
Likes: 4,389
From: Marlton NJ
I do not recall you saying if you checked your rotors for runout. They are "new" so that means they will have some runout, it's because of the old GM hubs.
Your left rotors appear to be original since they still have the factory rivits. The rotors on the right do not.
When the rotors pulsate the pistons, they pump air and/or water in behind the dust seals. It gets trapped there and corrodes everything. That was the "crud" you found.
Please check the rotors or your new brakes may not last long at all. Done right they are very reliable. But only when they have zero rotor wobble.
Your left rotors appear to be original since they still have the factory rivits. The rotors on the right do not.
When the rotors pulsate the pistons, they pump air and/or water in behind the dust seals. It gets trapped there and corrodes everything. That was the "crud" you found.
Please check the rotors or your new brakes may not last long at all. Done right they are very reliable. But only when they have zero rotor wobble.
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
I do not recall you saying if you checked your rotors for runout. They are "new" so that means they will have some runout, it's because of the old GM hubs.
Your left rotors appear to be original since they still have the factory rivits. The rotors on the right do not.
When the rotors pulsate the pistons, they pump air and/or water in behind the dust seals. It gets trapped there and corrodes everything. That was the "crud" you found.
Please check the rotors or your new brakes may not last long at all. Done right they are very reliable. But only when they have zero rotor wobble.
Your left rotors appear to be original since they still have the factory rivits. The rotors on the right do not.
When the rotors pulsate the pistons, they pump air and/or water in behind the dust seals. It gets trapped there and corrodes everything. That was the "crud" you found.
Please check the rotors or your new brakes may not last long at all. Done right they are very reliable. But only when they have zero rotor wobble.
This is where my head is at this time round... this was a quick fix to get back on the road and identify the bad calliper and cause of my braking issues. Due to the cost of imported goods over here in the UK, it was about $175USD just for the pads and rebuild kit for one calliper, not a huge amount less than brand new Wilwood (per calliper) without the design issues.
If I'm faced with more brake rebuild or component replacement costs in the future, or have to start spending time and money replacing rotors with run out issues, just to continue to fight against the endless tide of bad calliper design, I'll bit the bullet and go Wilwoods all round as I feel piling lots of (UK import costs makes this more of a financially viable plan) money into the current system is a false economy - in my world anyway.
Hope that makes sense.
Last edited by Last Triumph; May 15, 2022 at 04:10 AM.
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Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,035
Likes: 4,389
From: Marlton NJ
It is not hard to check the runout on the rotors. Especially for an engineer. Just use a dial indicator.
Correcting it is not difficult either, just time consuming. You can buy rotor shims or make them out of any convenient shim metal stock you can find. .001" to .004" thickness should be good.
There is just something satisfying about making an old car run "perfect" LOL
Correcting it is not difficult either, just time consuming. You can buy rotor shims or make them out of any convenient shim metal stock you can find. .001" to .004" thickness should be good.
There is just something satisfying about making an old car run "perfect" LOL
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
It is not hard to check the runout on the rotors. Especially for an engineer. Just use a dial indicator.
Correcting it is not difficult either, just time consuming. You can buy rotor shims or make them out of any convenient shim metal stock you can find. .001" to .004" thickness should be good.
There is just something satisfying about making an old car run "perfect" LOL
Correcting it is not difficult either, just time consuming. You can buy rotor shims or make them out of any convenient shim metal stock you can find. .001" to .004" thickness should be good.
There is just something satisfying about making an old car run "perfect" LOL
What would you attach it to as the fixed reference point on the car, given they are not held in place firmly with the wheel removed?
Race Director
Joined: Mar 2017
Posts: 11,929
Likes: 4,497
From: Virginia
I'm assuming you don't have rivets anymore, so be sure to hold the rotors on with a few lug nuts.
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
Attach the base to the trailing arm (rear) or spindle (front), with the clamp or the magnet. The runout relative to the brake caliper is what is really important, so for extra credit, you could mount the base to the caliper bracket. I'd think you'd want to test the runout with the caliper removed anyway.
I'm assuming you don't have rivets anymore, so be sure to hold the rotors on with a few lug nuts.
I'm assuming you don't have rivets anymore, so be sure to hold the rotors on with a few lug nuts.
Safety Car
Joined: Jul 2005
Posts: 3,691
Likes: 833
From: WI
I have some really heavy cast iron press-plates for a press. On some vehicles, like 4x4 trucks or a car where the wheel is up on jackstands, I put some water in a 5 gal bucket (for weight), and put a press plate on the lid. And attach the magnetic base to the press-plate. The bucket is pretty solid (as long as the concrete isn't uneven) and the press plate fits nicely in the center of the lid. It's pretty solid. But you could do something similar with some steel you might have around the shop, even if it's just 1/4" thick. It's a no-cost idea to keep in mind when you can't attach to a spindle.
Make sure to get some oversized nuts that'll fit over your studs ...and bolt them down. You really don't need to torque the lug nuts and rotor to spec tightness, to test for run-out, ...just get them fairly tight, before you test it with the dial indicator.
Make sure to get some oversized nuts that'll fit over your studs ...and bolt them down. You really don't need to torque the lug nuts and rotor to spec tightness, to test for run-out, ...just get them fairly tight, before you test it with the dial indicator.
Last edited by Mark G; May 17, 2022 at 01:09 PM.
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,433
Likes: 351
I have some really heavy cast iron press-plates for a press. On some vehicles, like 4x4 trucks or a car where the wheel is up on jackstands, I put some water in a 5 gal bucket (for weight), and put a press plate on the lid. And attach the magnetic base to the press-plate. The bucket is pretty solid (as long as the concrete isn't uneven) and the press plate fits nicely in the center of the lid. It's pretty solid. It's a no-cost idea to keep in mind when you can't attach to a spindle.
Make sure to get some oversized nuts that'll fit over your studs ...and bolt them down. You really don't need to torque the lug nuts and rotor to spec tightness, to test for run-out, ...just get them fairly tight, before you test it with the dial indicator.
Make sure to get some oversized nuts that'll fit over your studs ...and bolt them down. You really don't need to torque the lug nuts and rotor to spec tightness, to test for run-out, ...just get them fairly tight, before you test it with the dial indicator.
One of the many challenges we have being in the UK and of metric persuasions, is that regular lug nuts of American threads just aren't in a coffee pot on the shelf waiting to be sorted through to hold the rotor in place, nore a collection of American taps to create at will. I'll figure something out.
Le Mans Master
Joined: Jun 2006
Posts: 6,399
Likes: 1,226
From: Tampa Florida
Gotcha.
One of the many challenges we have being in the UK and of metric persuasions, is that regular lug nuts of American threads just aren't in a coffee pot on the shelf waiting to be sorted through to hold the rotor in place, nore a collection of American taps to create at will. I'll figure something out.
One of the many challenges we have being in the UK and of metric persuasions, is that regular lug nuts of American threads just aren't in a coffee pot on the shelf waiting to be sorted through to hold the rotor in place, nore a collection of American taps to create at will. I'll figure something out.