M635CSI (EU M6) Brake Upgrade Advice

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Boggie
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M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

HI All,

First post newbie so be gentle... :)

I have just bought a 1985 BMW E24 M635CSI to restore. It is a Metallic Black car with Oxblood-Red leather interior and in pretty good condition. It was restored (new panels, bare metal respray) 20 years ago, used for 5ish years then stored in a barn for the last 15. I have had my eye on it for a while as it was always one of my dream cars as a kid and last week I finally persuaded the owner to let it go. We did a deal to part-exchange with the 1966 Land Rover I recently finished restoring and now the shark sits in my workshop! :)

First thing to do is fully recommission the car. New tyres, hoses, fluids, service parts etc so I am looking into sourcing the parts.
One thing that definately needs replacing is the braking system. I am going to replace brake lines, fit braided hoses and new seals to the master cylinder etc. Whilst I am at it I would like to consider an upgrade to the brakes as I have read a number of reviews that say the standard items lack feel and power. However, I would like to keep the car as original as possible so the idea (and cost) of fitting Brembos or AP is out of the question.

After some research I came up with the following information:
  • The best upgrade at a reasonable cost is E31 front callipers/rotors and E34 540 rear callipers/rotors.
    The best upgrade for the least possible cost is E32 750 front callipers/rotors and E34 540 rear callipers/rotors
Would these options require just the rotors and callipers (IE bolt to the standard M635) or would I need to get hangars too? Should I only upgrade the front as the rears do very little work anyway? Also, would the standard master cylinder be OK with a modified setup?

This seems to be repeated in a number of places but is referring to an upgrade of the standard E24, rather than the M6/M635CSI car which had a better braking system anyway. I would really appreciate some advice from you experienced E24 owners. Would it be best to simply restore the existing M635CSI braking system, upgraded with braided hoses all round and performance pads? Or should I upgrade and if so, what is the best way to go please?

Many thanks,
Ian

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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

Congratulations on your purchase.

I assume it is #313. Has it still got C635 FKM as the reg? Seat colour should be Cardinal Red #0256.

S/S hoses and uprated pads are a reasonably cheap way to go.

Great place to overhaul your calipers (much cheaper than Biggred!)

http://www.classiccar-brakes.co.uk/

Are you using this for your parts search?

http://www.realoem.com/bmw/enUS/select? ... series=E24
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

Thanks Ron!

Thanks for the info, I will have a good rummage once I am out of this meeting. No, mine is on a B plate and before that on a couple of personalised numbers.
How do I ID what # number it is please?

Cheers,
Ian
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Soperman »

Congratulations indeed Ian on your acquisition. It's great to see another M635CSi re-commissioned and brought back to its former glory. You have certainly found what is unquestionably the best resource for knowledge, opinion and advice for these cars - thanks in no small part to the contributions of "Ron" and his invaluable experience.

Ron - I doubt very much that Ian's new car is number 313, which is a well maintained and preserved car with ultra-low (circa 18k) mileage. I seem to recall Munich Legends sold #313 about 6 years ago, asking a phenomenal £45k at the time.

Ian - the i.d number we're referring to is simply the last three digits of the VIN. Look in the engine bay, on the plate next to the top of the drivers side strut mount.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

Soperman wrote: Thu Feb 01, 2018 12:47 pm Ron - I doubt very much that Ian's new car is number 313, which is a well maintained and preserved car with ultra-low (circa 18k) mileage. I seem to recall Munich Legends sold #313 about 6 years ago, asking a phenomenal £45k at the time.
Thanks for the info. Mike. # 313 was the only Diamond/Red interior I could find. Maybe the interior has been replaced.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

That makes mine #071 but please don't post the registration plate details. I didn't think the interior has been replaced as i have a huge history file with recipts for everything from new, including the original BMW delivery info. I will check tonight. If you do have any info relating to this car I would be grateful if you could send it by email of private message. Thanks.

Despite it being in sound condition there are a lot of jobs to do. My list runs to 2 sides of A4 paper and still growing. Under all that 'barn lacquer' the paint is rather good. After a painstaking wash, cut back with 2k paper and a few minutes mopping has resulted in my test patch on the boot looking like wet glass. However, half of the panels have minor teltale bubbling that indicates I need to cut out some steel and joggle in some fresh new stuff. With this being both metallic and black it will be impossible to match/ blend in the new paint to the standard I want so I will have to spray the whole car.

I will still cut and polish the car so it looks good for now (the areas are very small) and once all the important stuff is complete I will at least I have a good base to work with. As it has been sitting in a barn for 15 years, I know any 'surprises' have by now shown themselves...
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by wattsmonkey »

Hi Ian,

Welcome! My M came with upgraded brakes from the 8er, which are the "Brembos" referred to in the upgrades. They work very, very well but lack feel - especially in the stop/start traffic that the M cars don't have much love for in any case. I have reverted to the original set up (thanks to Ron's help) and the feel is much better. I am considering more aggressive pads for the front.

I have upgraded the rears to the E34 540i setup, although the non-vented rears from any E34 would probably be as good.

Do stick some pictures up and let us know where you are.

Cheers,

Rob
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

#071 was built with "anthracite cloth" interior (code #0186) and had Recaro seats.

Had RA 100 reg.at one time.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

Interesting, thanks.

I will have another dig through the telephone-book size pile of receipts, maybe I missed it on first pass.
That puts me in a dilemma; Where possible I like to restore cars to their original specifications, apart from sensible upgrades (EG servo brakes and R/P steering etc on older cars). Therefore Ishould remove the current seats / door cards / rear shelf pods etc and source some anthracite cloth. However, those red leather Recaros look fantastic and are in excellent condition. A good clean and leather feed has brought them up well and there is hardly any wear, even on the driver's set bolsters. I guess I could file them under sensible upgrades.... :)
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Soperman »

I guess Ian, that your dilemma might be easier to resolve if you are completely sure that the seats currently in your car are genuine Recaros, and not the customary BMW Sports Seats.

Forgive me, but I only infer a degree of doubt because it they do look rather similar, and many people have in the past got confused.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

No Problem. Grateful for the input.

There is no Recaro badge in the back rest but they do look like Recaro seats. At least they look like all the 80s vintage Recaros I have seen owned, seen or worked on in the past. IE all the levers are where I remember them being, they have the wind-out knee supports and are very definitely a Recaro shape... I had assumed that BMW got Recaro to make the seats for them but didn't know there were both BMW and Recaro as options in the M635. I know there were electric and manual, depending upon year. Mine are all manual.

How do I ID the BMW Sports Seats please?
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

E24 Recaros do not have wind out knee supports.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

Some Recaros do. They did in my Delta HF Turbo and Integralé and also RS Turbo MK1 Escort. I don't think my Capri 2.8 had the knee supports but I am pretty sure the Brooklands 280 did.

Are you saying that when Recaro seats were fitted to the BMW E24 M series cars, they were the more basic version with non-ajustable knee supports?
That might answer my question.

So, do I have the BMW sports seats then? I wonder if Recaro made them for BMW.

Thanks,
Ian
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

Soon tell with some pics.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by GazM3 »

Yeah the 540 rears are a good upgrade with std fronts and upgraded pads and braided hoses. I have an e32 750il 25mm master cylinder which gives good pedal feel also.

This works great on mine. I’ve only got low dust pads so even with these it stops hard on the odd mountain pass when pushing the car hard.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by randall977 »

Very nice, have you driven it yet?
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by wattsmonkey »

BMW leather sports seat in pearl beige, sitting pretty in a 635. Confusion often caused because they are referred to as a Recaro design.
sport seat.jpg
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

Thanks Chaps!

They are the very seats! Although in my car they are red. So, mystery solved :) Here are mine after removing, deep cleaning and 2 treatments of Liquid Leather feed. Another coat in a week then leather seal to finish them off....
Image

Next mystery is the anthracite cloth Ron noted was listed on the car. I spoke to the original owner today. Initially it was owned by his work as a company car, he bought it from them at the end of its' tenure. He said that when he bought the car it already had the red leather seats and he is pretty sure it came like that new... Assuming the info Ron has came from BMW, I wonder if the company asked for a late spec change and the dealer fitted them before delivering the car?

Very pleased to see BMW still stock parts for the car although I have not stretched them much yet. Yesterday I collected plugs, plug tool, air filter, Oil, Oil filter and o-rings, Rotor arm etc and spent yesterday servicing. After a good check of brakes, steering, tyres etc I took it for a cheeky drive today (as it is not road legal yet) and it drove surprisingly well considering it has not been run for over a decade.

Despite the car getting up to temperature I wasn't getting any heat in the car so I guess there is an electric valve somewhere that is stuck. Need to investigate...

Cheer,
Ian
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

Ian,

Next time you are in the "stealers" ask them for a build sheet for your chassis #.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Soperman »

Hi Ian.

I must say, your (Taurus?) red interior is rare, distinctive and extremely attractive, but I cannot help but feel that the original owner might have got his wires crossed somewhere.

I have worked, for a period of many, many years, at a variety of new car franchises, and have rarely encountered the situation whereby a dealer has been prepared to risk the numerous and undesirable complications by agreeing to swap out interiors before handing over a NEW car. Now that's not to say it couldn't have happened, but it does seem even less likely when one considers the very short period of time that lies between #071's factory build completion date (March '85) and it's UK registration date (April). Consider also the fact that it's first registration number was a "cherished" one, and it seems as your car was atypical in being built-to-order for a specific customer who purposefully desired cloth upholstery, and was keen to get his hands on his just-released-in-UK M635CSi as soon as possible.

If you ever watch across the "Wheeler Dealers" 635CSi episode where Mike Brewer buys a donor car at just to replace the unfancied cloth interior of his project with a more sale-able leather one, it becomes easier to appreciate how simple it might have been for the restorers of your car to make the same decision, as I presume they did 20 years ago.

I think anyone who makes the admirable decision to get a car back to original spec should be commended, as I would always look to do the same. But I reckon finding an original replacement E24 cloth interior with the correct Recaro seats is just impossible.

Faced with the same dilemma, and taking all the above into consideration, I would stick with the existing, glorious interior and plough my efforts and resources into getting the car back on the road - legally!

I apologise now for offering this unsolicited opinion.

Best of luck with your re-commissioning, and I'm looking forward to reading more encouraging news about its progress.
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by Boggie »

Thanks Chaps,

That is about as much as I thought too. However, the car was definitely originally sold to a company as I have the paperwork. I assume the cherished number either belonged to the company's or the driver (I am guessing he was quite high up in the company considering the cost of these cars back then). The guy who I spoke to was an employee who bought it from the company, I guess when it was around 3 years old. He said he was the second owner and seemed pretty sure the car had red leather when he bought it but I agree with your conclusion; it doesn't seem to match up. He did own the car for quite a while and sounded quite old so perhaps he was confused...

However, I agree with your other conclusion that it will be hard to fine decent cloth interior and the red seats fitted to the car are the correct make and type, and they look really good.

Ron, as usual is on the money. I double checked with BMW this morning and they confirmed the cloth seat option.

Cheers,
Ian
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Re: M635CSI (EU M6) Brake Upgrade Advice

Post by ron »

Boggie wrote: Mon Feb 05, 2018 7:45 pm Ron, as usual is on the money. I double checked with BMW this morning and they confirmed the cloth seat option.
I have the build sheets for all of the UK M635s.
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