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hello folks London calling well I am in the UK other side of the pond I have an issue will try to upload pictures. I gave my 6 pot Alcon monblock aluminium brake calipers to a brake caliper refurb specialist he was going to strip both calipers down replace rusty pistons with stainless steel pistons and new seals all round as well as bleed nipple.
on return of my calipers I noticed he had whilst in his care damaged one of the calipers. The damage was around the middle piston it has a raised circular edge where the piston slides up and down on into its bore. when they tried to remove a dust seal they must have prised it out and caused the aluminium cast to snap away leaving a gap exposing the new dirt seal. I was not happy informed them I wanted a new/used bare bones caliper body and everything good removed from damaged cast and transplanted into replacement body.
They have now told me they have machined the remaining broken lip down and some how machined another circular washer and now informing me they have pressed and bonded this down to the caliper and after they finish repainting its good to go again???
I am not so sure. I value other peoples input on the issue. I will upload picture of caliper before it was reconditioned. I will try to upload pictures of what state they are in currently.
Simple logic, never use a damaged core. I would find a new core and have him pay for it. I would think a rebuilder with any reputation would go along with this. It may take you a while to find one, you can contact one of the US based dismantlers.
Thank you for input this is what I thought but I did not want to give the impression I am being difficult with the brake overhaul specialist.
this is his latest email
" Hi Zak just thought I would update you the casting with the broken dust seal shoulder is being repaired. We have machined the fractured section off and machined a new retaining ring an exact replica of the casting. This will be pressed and bonded using similar technology to Land Rover when they bond their bodies together. It will be as strong or even stronger then the 1mm of original casting.
We have spoken to Alcon who have confirmed this retains the dust seal only. They also said when these calipers are used for racing they remove the dust seal as it overheats. We are blasting them back to bare metal again to see if we can sort the paint work. I will be in touch kind regards
Seems as though the caliper restoration company is going out of their way to make it right, as opposed to disappearing when it comes to a claim like yours. I think this is admirable customer service, that isn't standard anymore.
Let's see the end product before you blacklist them. I think they will make it right.
Seems as though the caliper restoration company is going out of their way to make it right, as opposed to disappearing when it comes to a claim like yours. I think this is admirable customer service, that isn't standard anymore.
Let's see the end product before you blacklist them. I think they will make it right.
Good luck.
The rework approach makes sense and as long as the caliper will continue to accept OEM dust seals, I think the caliper will be as good as it can be considering its before repair, state. If it does not accept an OEM seal, I would reject their proposal and insist on a new/used core.
Here are a few other thoughts...
One irritant that I noticed is that they also painted the caliper mount landings which is (or was originally) hard anodized to withstand the rigors of heat and braking stresses. How long before the paint breaks down and the fastening torque of the calipers has been diminished?
Tell them to please remove the paint from both the bottom and top mount surfaces of the caliper!
Looking at the before photo of the caliper, one can plainly see that the mount surfaces of the caliper are significantly corroded. This would also lead me to believe that the piston bores are equally, if not more so corroded...The caliper appears to have been rode hard and put away wet!
Taking these factors into consideration; in my head, a proper repair of this caliper (if not throwing it away) would include a minimal skim cutting of the mount faces (.005") including re-hard anodizing; and re-boring the piston bores the next size over, utilizing next size over, piston seals.
If this caliper is being saved solely upon the fact that it is a 6 pot caliper, I think that rationale should be examined more closely as well.
P.S. I apologize for the long dissertation, here... I used to disposition non-conforming material in the aircraft and aerospace industry on behalf of the DoD.
Just a rubber dust seal, not a big deal, it's not a metal part that is broken here so don't worry too much, however on the refinishing end, those look a little rough on the refinishing work...
You can see that black area, these are rubber seals
A closer look at these rubber dust seals
I used this one so you can see the yellow that was painted by the previous owner, they painted the rubber seals, we masked them off completely while refinishing and that is why you can still see the yellow over-spray on those.
Just a rubber dust seal, not a big deal, it's not a metal part that is broken here so don't worry too much, however on the refinishing end, those look a little rough on the refinishing work...
I'm not sure we're looking at apples to apples here. The image posted is clearly not an Alcon 6 pot caliper and its what is under the rubber seals that we are concerned with.
Also, when I refinish my calipers, I removed the hardline crossovers in addition to the bleed screws and plugged the ports, while masking the boots and caliper mount landings as well. Due to the incomplete refinishing behind the hardline, (enlarging the photo) you can see this was not done in this application...
You can see that black area, these are rubber seals
A closer look at these rubber dust seals
I used this one so you can see the yellow that was painted by the previous owner, they painted the rubber seals, we masked them off completely while refinishing and that is why you can still see the yellow over-spray on those.
Just a rubber dust seal, not a big deal, it's not a metal part that is broken here so don't worry too much
The slight overspray on the boot is meaningless and insignificant; however, the OP's caliper has a broken metal retaining part that holds the dust boot into place. The repair disposition clearly states this fact!
We have machined the fractured section off and machined a new retaining ring an exact replica of the casting. This will be pressed and bonded using similar technology to Land Rover when they bond their bodies together.
Looking at the before photo of the caliper, one can plainly see that the mount surfaces of the caliper are significantly corroded. This would also lead me to believe that the piston bores are equally, if not more so corroded...The caliper appears to have been rode hard and put away wet!
I noticed this too, although not until I saw the yellow painted version. The mounting surface has clearly corroded away quite a bit.
One of the pistons has some corrosion on it as well.
On the positive side, this company does seem to be trying to make it right, FWIW.
Just a rubber dust seal, not a big deal, it's not a metal part that is broken here so don't worry too much, however on the refinishing end, those look a little rough on the refinishing work...
You can see that black area, these are rubber seals
A closer look at these rubber dust seals
I used this one so you can see the yellow that was painted by the previous owner, they painted the rubber seals, we masked them off completely while refinishing and that is why you can still see the yellow over-spray on those.
The dent marks on the aluminium housing was caused by me
I was hitting them with a metal head hammer trying to shift them off the disc because I am stupid lol I should have used a piece of wood in between to soften the blows.
I am at a stage where I am more interested in function rather then cosmetic appearance although saying that they are being repainted.
I wanted paint rather then powder coat as I was informed paint is better in getting rid of heat as powder coat acts as a insulator. I was annoyed that the dust seal was exposed like that on my particular design of calipers because under normal conditions they are seated in a ring inside the bore.
I felt with a dust seal exposed by 40% then this seal will elongate and not sit correctly after a few heat cycles once the caliper is used. The effect would be tiny ingress of dirt towards the more important fluid seal. I felt if dirt contamination happened near the fluid seal then a risk of leakage is possible and hence brake failure eventually over time.
I know the brake failure will occur slowly as I will feel it in the brake pedal when I brake that I am losing the pedal similar to when you have air in the fluid.
I am concerned now that because I was not present in the repair works that if they have simply ground down remaining aluminium ring and just super glued another washer like ring on top which could possibly be a different material like iron super glued to Aluminium this will cause issues under several heat cycles in the long term and might not be a sustainable fix.
the merger of one metal on to a different metal using some sort of mystery bond agent supposedly being pressed in which I cannot understand how with out damaging the dust seal?
I will know more when I go to collect these but I am not happy to part with my money unless I know a proper fix has been completed. I would have preferred a core exchange new or used and everything swapped across.
I am not to keen on modified fixes as these calipers are one piece cast from a block of Aluminium not a mixture of metal parts
08-30-2017, 02:40 PM
Advice needed re Alcon calipers ruined
