Brake Drum Quality

[DJT]

I know that parts quality has been discussed several times before, but mainly regarding rubber parts.

My latest job on the Stag is to try and eliminate the 'advisory' I've had on the past three MOTs, namely:

• slight fluctuations in rear brake test readings.

As such, I have bought new drums, shoes and cylinders. The shoes and cylinders were last replaced in 2008 - 34,000 miles ago - not long after I bought the car. The drums appear to be originals as they still have the Stanpart logo.

The new drums arrived and I am not exactly overwhelmed by the quality.

Eccentric machining:

IMG_0530.jpg

Poor machining:

IMG_0531.jpgIMG_0533.jpgIMG_0534.jpg

I have spoken to the supplier, who 'assures me' that hundreds of these have been sold, with no complaints, and others in stock are the same. They have spoken to the UK manufacturer who say the same. I have spoken to another parts supplier, who confirmed that they get their drums from the same manufacturer as the original, and that they fit dozens of these per year in their own workshops.

I have subsequently found out that these drums are cast in Turkey, then machined in the UK which entitles the manufacturer to stamp them "Made in the UK".

Why can't parts like these be machined properly? I can buy brand new discs for my modern cars from ECP for less than £20 each, and they are perfect. These drums cost around £45 (+VAT) each. I'd happily pay an extra tenner or so to have parts that look as if they have been machined properly. i.e. made to a standard, rather than down to a price........

I've got 3 choices here:

• Fit them
• Return them (£15 carriage)
• Pay to get them machined properly at a local engineering shop, which will double their price.

[Stagnant]

Dave, I had a similar experience with some power steering hoses recently that just didn’t fit. I contacted the supplier who gave me much the same assurances that you got - and much the same options. In the end I carefully bent them to fit. Not just one, but both of them. Ok, so they fitted in the end but they weren’t just a couple of mm out, they were pretty far off the mark. What disappointed me the most was the lack of willingness to rectify the problem. I have since changed supplier but I doubt they’ll notice or care!

[Registrar]

Dave,

I can't quite get my head around this without seeing the drums and thinking for a long time but is this a case of poor casting ?
The machining has to be done from some kind of datum point - possibly the central hole - but if the casting is 'lopsided' then the mis-shape can't be machined out.

One of the things which I have wished for a long time is that someone in the Club would start an assessment or comparison of parts which are currently for sale with the originals so that we would all know what we were buying and how they compared to the originals. The Club has always stayed away from anything like this, probably due to the possibility of falling out with a supplier or, even worse, being sued by them for potential loss of business. I have wanted to see these 'reports' in the magazine but in an absence of such technical comparisons the Forum does a good job of bring things like this to all our attention, perhaps there should be a special section to where the threads could be copied to bring them all into one place, then we could easily look for comments on a part when thinking of buying and thus know what we are likely to get ?

Peter

[mike@thenook]

perhaps there should be a special section to where the threads could be copied to bring them all into one place,.....

Great idea Peter, let’s see if this can be done....

[Phil S]

I fitted let's say "made abroad" discs to the front of my first dax rush.
After 2 sva fails l found the discs had started to blue a little with use.
This lead to me being able to see that they had been cast from various scrap material that had not mixed well and they were visibly patchy.
When tested with a file some parts were soft others the file skated across, no wonder the braking was poor.
EBC discs cured the problem.

Can we rely on "quality" products made abroad?

Phil

[mole42]

Unless a parts supplier has adequate (=expensive) incoming quality control it doesn’t matter where parts are made. Unless the supplier bothers to check the incoming inventory against the specification there will always be those parts that are not fit for purpose.
What bothers me is that many parts suppliers don’t check and give out the old guff about “no-one else has had a problem”.
It’s not just car parts either.

[MandM]

Dave,

I can't quite get my head around this without seeing the drums and thinking for a long time but is this a case of poor casting ?
The machining has to be done from some kind of datum point - possibly the central hole - but if the casting is 'lopsided' then the mis-shape can't be machined out.

One of the things which I have wished for a long time is that someone in the Club would start an assessment or comparison of parts which are currently for sale with the originals so that we would all know what we were buying and how they compared to the originals. The Club has always stayed away from anything like this, probably due to the possibility of falling out with a supplier or, even worse, being sued by them for potential loss of business. I have wanted to see these 'reports' in the magazine but in an absence of such technical comparisons the Forum does a good job of bring things like this to all our attention, perhaps there should be a special section to where the threads could be copied to bring them all into one place, then we could easily look for comments on a part when thinking of buying and thus know what we are likely to get ?

Peter

Can the SOC work with all the suppliers and Build a SOC approved parts system, it would be in their interest as well as they would obtain more sales?, as we all get pissed off by poor parts and service.

[Registrar]

The problem has always been with us but it seems to have got a lot worse in the last few years. I'm now scared of ordering any new parts.

We are already working with suppliers in respect of SOCTFL, if we had a will (and enough member support) surely we could extend our relationship to at least understanding more about the parts supply process and helping parts suppliers to achieve better quality control.

We don't currently have a will at Committeee level. What can members do to instill a will ? One way would be to volunteer to assist in some way with engineering projects or assessments. A number of our members are technically competent, how do we take this forward ?


One of the problems we have is

How do you return four pallets of poor castings to Poland and expect to be reimbursed and I suspect that the poor machining is actually a way of reclaiming out of spec work in the first place. To make the wall thickness vary you have to reset the workpiece between machining operations - which no self respecting machinist would do unless they were trying to make sure that they had a fully machined rim. Of course they could have machined the central hole incorrectly in the first place which put the rest of the machining processes out of true but, basically, having to reset the machining position between operations is not what anyone would do out of choice.


Peter

[Mark Serj]

I come from the aerospace industry where our suppliers cannot supply without certain stringent approvals plus regular audits. Is there no similar (but perhaps less stringent) car industry system? after all, cars are potentially lethal transportation devices.......

[milothedog]

I come from the aerospace industry where our suppliers cannot supply without certain stringent approvals plus regular audits. Is there no similar (but perhaps less stringent) car industry system? after all, cars are potentially lethal transportation devices.......

Not sure if there are any for our parts ? but you could look for and buy from a supplier that is ISO 9001/2 accredited. This was the case in my company (The Bus Industry) but like your industry ours was public transport so safety was more of an issue than in the domestic market.

[barkerwilliams]

Mark,

Out of curiosity I looked up the price of a Cessna brake drum $2,850. Quality comes at a price.

Alan

[Kithmo]

Mark,

Out of curiosity I looked up the price of a Cessna brake drum $2,850. Quality comes at a price.

Alan

Do they fit the stag ?

[Mark Serj]

Ha ha nice one! Trouble is anything associated with aerospace is extra expensive!

[dasadrew]

Perhaps relevant to the Stag situation, we had an opportunity at work to use a Brembo BMW motorcycle brake disc for an aerospace application. When we approached Brembo with the quality requirements including each disc having to have an individual serial number and log card, Brembo asked how many did we want - 10,000? 15,000? 5000? When the answer "200 or so" came, Brembo suggested we get on our bike (presumably a BMW one!)

Quality is expensive and only really pays off when it can be amortised over a high production number. What sort of production run numbers do Stag parts generate?

Drew

[DJT]

What sort of production run numbers do Stag parts generate?

Drew

Drew,

I was told, by the supplier, that the manufacturers had sold 600 of these drums, without complaint. At least 2 of our regular suppliers are currently waiting on new stock to be delivered. I have no idea over what period they have supposedly sold these 600 Stag drums.....