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Dart Brake Calipers

daimlernorm
Posts: 12
Joined: Tue May 02, 2017 5:48 pm
Location: Preston Lancs England

Dart Brake Calipers

Post by daimlernorm »

I am planning to get my Brake Calipers refurbished, I have found a couple of companies who can do the work,
they are BCS Automotive in Nottingham & Classic Brake in Chelford, has anyone used either company and were they
happy with the standard of work.
Norm

Vortex O'Plinth
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Re: Dart Brake Calipers

Post by Vortex O'Plinth »

I've not used either company but if you get negative reports a capable alternative is Past Parts in Bury St. Edmunds.
Nick

"Don't bother with the Air & Space Museum - there's nothing to see.......".

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SteveW62
Posts: 101
Joined: Sat Feb 13, 2016 5:45 pm
Location: Germany

Re: Dart Brake Calipers

Post by SteveW62 »

I've used Classic Brake at Chelford for all my calipers in the last 10 years ( All 4 Daimler Dart, TR6, Jag 3 Pot, TVR & Caterham )

I can only highly recommend them. The turn around is pretty quick & I find the Prices OK.

What really impressed me was when I originally took in my Dart rears & put them on the counter, John ( or maybe Lee ) said "Wow, Daimler Dart .... you don't see many of those nowadays". They know their stuff.

Here's a link to what they did => http://archive.dloc.co.uk/forum/topic.a ... ichpage=2&

All the Best
Steve

daimlernorm
Posts: 12
Joined: Tue May 02, 2017 5:48 pm
Location: Preston Lancs England

Re: Dart Brake Calipers

Post by daimlernorm »

Hello Steve, thanks for the posting & photo regarding Classic Brake, I have contacted
Lee at Classic Brake so just need to get the Calipers off the car but will leave it until
next week cos out on a drive it day run tomorrow around East Lancs ending up at Lancaster Brewery

Cheers
Norm

tjt77
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Re: Dart Brake Calipers

Post by tjt77 »

Interested to know if its common to replace the front calipers for modern equivalents on the SP 250 ... I almost always upgrade the front brakes on anything with dunlop calipers as its generally less money and one ends up with better brakes ( 4 pistons and more than double the pad area = better stopping) that are much simpler and pad changes become easier too.. the 'coppercraft' front caliper conversion for the Etype/Mk2/Daimler 2 1/2/V8250 should be a direct bolt on to the SP ( tested it on an MGA 'deluxe' with same brakes ..all lines up perfectly) in USA a more common alternative is the wilwood conversion.. not quite as 'clean' as it utilizes an adaptor bracket for the caliper body.. coppercraft is straight 'bolt in' ..no messing with shims etc.. and one part of that kit can be eliminated..the link hard line from caliper to flex line.. the flex line can be bolted straight into caliper.. provided the flex line is modified:- approx 3/8" cut off the the end that would have joined hard line, a copper washer added and the line bolted straight into back of caliper.. ( Ive only done this on one car so far.. Mk2 jag with a steering rack conversion.. no issue with flex line hitting anything and hence chafing over full suspension travel and testing lock to lock ) reproduction dunlop cylinders are readily available from various suppliers also..

Im still getting rear calipers rebuilt due to economics.. the 1 1/2" cylinders remain pricy.. but rebuild ( rebuilder I use lines them with brass) is same cost as rebuilding the 2 1/8" cylinder.. also some 60s Datsuns had dunlop front disc brakes that were made under license ..those cylinders ( marked 'dunlop sumitomo') are not only better quality than the original dunlops.. they are cheaper to buy outright.

Ian Slade
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Re: Dart Brake Calipers

Post by Ian Slade »

The SP brakes are Girling, the front pistons and seals are Ford Corsair, the Pads Zephyr Mk 4 I seem to remember, the rear pistons and seals are Jaguar MK10 can't remember the pads but were one of the common cars. I remember looking at a 4 pot replacement front caliper and thought the Volvo 145 estate could be made to fit.
Owner since the 70's, Genghis is slightly to my left.

timmartin
Posts: 65
Joined: Wed Feb 17, 2016 1:37 pm
Location: Berkshire

Re: Dart Brake Calipers

Post by timmartin »

Front brake caliper interest me too.

Features of alternative types that would interest me most are increased piston area and the opportunity to operate both front calipers from two circuits (which seem a good idea to fit anyway).

I have owned two 100 series and two 200 series Volvo estates and both had this feature. I once had a single circuit brake failure on one of them, and the only difference that I noticed was the warning light (which was triggered by a simple switch which was operated when the pressures in the two brake circuits were not equal). Reassuring.

I have never suffered brake failure in the SP, but have spoken to several people who have. I have also experienced clutch master cylinder leaks (past the piston seal, into the car, and down behind the carpet leaving everything looking clean and healthy). Once I detected the fluid loss before the clutch stopped working. Once I didn’t. Inconvenient. Glad it wasn’t the brake.

Regarding piston area per caliper, an increase on the front would move the brake bias forward (which seems safer to me - I am no racer) and would tend to reduce the pedal pressure for the same braking effort. Additional care would be needed with trueness of discs to prevent worsened “double pedal” trouble due to “pad knock back”.

I cannot comment on the benefits of larger pads under hard use, but I believe that under normal use retardation is virtually unaffected by pad area, and principally governed by applied force and coefficient of friction.

The only time that I looked into an alternative four pot caliper, I found that the piston area of two little pistons was no greater than that of the existing one big one. Since the manufacturer said that the two little pistons couldn’t be operated on separate circuits (like the Volvos) I rather gave up. It was beginning to look like an expensive route towards non standardisation for little if any benefit.

So the above discussion about alternative calipers reawakens my interest.
Tim
Blue 1964 SP250 in Berkshire

Vortex O'Plinth
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Re: Dart Brake Calipers

Post by Vortex O'Plinth »

Robert Grinter offers a Jaguar 3-pot caliper conversion for the SP. I haven't fitted them but apparently they're a straight swap needing only the splash shields to be trimmed.

On the subject of brakes, my SP has featured the 'double pump' brake action ever since I acquired it 45 years ago. Even after a recent complete restoration, including new discs all round, rebuilt rear axle, fully overhauled calipers, new front hubs and bearings, new master cylinder, new brake lines and fittings and new Goodrich hoses, it was still the same - and yes, I've checked disc runout, hub bearing clearance, and bled the system within an inch of its life.

Some recent intermittent brake light operation was traced to a faulty brake lamp switch, so I bought a replacement - which unusually was a NOS Lucas original in a red box rather than the modern green box repro's. Anyway, after fitting the switch the brake lights are now not only reliable but an unexpected side effect has been that the system now offers a hard pedal on first push every time. Can see no logical explanation except perhaps that the old switch (which was itself a modern replacement) somehow trapped air which could not be successfully bled?
Nick

"Don't bother with the Air & Space Museum - there's nothing to see.......".

daimlernorm
Posts: 12
Joined: Tue May 02, 2017 5:48 pm
Location: Preston Lancs England

Re: Dart Brake Calipers

Post by daimlernorm »

Interesting comment Nick about double pump on brake I have to do the exact same when braking on my SP
could you advise the Lucas Part No. for the Brake Lamp Switch.

Norm

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Re: Dart Brake Calipers

Post by Vortex O'Plinth »

daimlernorm wrote: Tue Apr 24, 2018 4:03 pm Interesting comment Nick about double pump on brake I have to do the exact same when braking on my SP
could you advise the Lucas Part No. for the Brake Lamp Switch.
The 'double pump' brake pedal action is experienced buy many SP owners Norm. If you search the forum you'll find several sensible suggestions that owners have found cure the problem - replacing perished brake hoses and tightening up the front wheel bearings being two examples. As I stated, none of these logical solutions had any effect on my problem.

I can offer no guarantee that replacing the switch on your car will have a similar result but for what it's worth the original Lucas switch part Number is 3980003. There are modern replacements for the Lucas original available from several sources - this one for example. I actually ordered from this site but instead of the switch illustrated (in the green box) Iactually received a Lucas original - like this one.

The Lucas original has a larger body than the modern replacements, although the thread is the same. Whether this has any relevance to the problem I have no idea.
Nick

"Don't bother with the Air & Space Museum - there's nothing to see.......".

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