Brake upgrades

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Dave Meyer's write up


see Brian (F1 Lotus) but in the meantime.....

Wilwood 16" installation on UK S2

For the 16" kit I used:

  • 2 off custom brackets (Brian).
  • 2 off custom hats (Brian).
  • 2 off Wilwood 4 pot Caliper (Rally Design 120-6806) - the inlet is 1/8-27 NPT and not directly compatible with OEM hoses. NB corrected from 120-6816 as originally in this article. Brian F1Lotus spotted the error here:
  • 1 off Wilwood Pads (Rally Design 15Q-6824K).
  • 2 off Wilwood Discs/Rotors (Rally Design 160-5844).
  • 2 off brake hoses (Brian) - replaced with shorter Goodridge stainless hoses or place 1/2 twist in Brian's when installing.
  • 16 off 5/16"-24 x 3/4" bolts {hat to rotor} (2 off Rally Design 230-0150 (8pk)).
  • 4 off M12x1.5-35mm bolts, property class 10.9 (SAE grade 8) preferred. Note, the 1.5 pitch is considered "fine thread". Attach (Brian's) caliper brackets to the car.
  • 4 off M10x1.5-30mm socket head bolts. 1.5 pitch is normal, not fine, in M10 size. Attach the Wilwood calipers to (Brians') caliper brackets.

Fitting Procedure

1. Loosen wheel nuts.

2. Jack up and support with axle stands.

3. Remove wheel and angle the steering so that the front of the hub carrier is more accessible.

4. Remove two caps from caliper retaining bolts, using penknife and/or screwdriver to expose the caliper retaining bolts.

5. Remove the two retaining bolts (10mm) and swing the caliper back out of the way.

Note: the retaining bolts are 12 mm on an S2 and the threadpitch is 1.5. This is important for point 6. when taping the hole.

6. Clean the back of the hub carrier and make sure the threads are clean ALL THE WAY THROUGH. This is important otherwise you will stretch the bolts or inadequately torque up the new calipers. If you haven't got the requisite taps, cut four grooves in one of the old bolts and use that to clean up the threads - use it as a tap and take your time with ½ turn in and a whole turn out when it starts to bite.

7. Remove the disc retaining screw (4mm). Note the trouble I had getting mine out, resorting to mole grips in the end.

8. Gently tap around the edge of the disc with a copper mallet or similar until it releases, taking care not to hit the suspension and making sure to catch the disk when it does give.

9. Clean the hub and the tapped threads for the retaining screw as above.

10. Admire the effects of the British climate on cast iron.

11. Smear Copaslip or similar around the back of the hub carrier and offer up the Wilwood caliper bracket. Apply Loctite 971 or similar and insert the 2 high tensile retaining bolts {SIZE????}. Torque to the recommended torque and admire your handiwork.

12. Offer up the top hat to the disc; Apply Loctite 971 or similar and insert the eight bolts with lockwashers. Using a 6mm hex allen driver, torque to the recommended torque. Wipe any excess Loctite off the rear.

13. Copaslip the hub and offer up the disc to the hub; insert the retaining screw.

14. Insert the right angle connector into the Wilwood caliper, angling the exit towards the top of the caliper. Screw in the hydraulic hose then offer up the caliper to the bracket. Apply Loctite 971 or similar and insert the 2 high tensile retaining bolts {SIZE???} Torque to the recommended torque and admire your handiwork.

15. Check that the disc is centrally aligned between the caliper.

Important note: I have Brian's original hat kit. To correctly install these hats, they need a 45 degree champfer machined on the inner face of about 3mm. just compare the hats to the original discs. I feel this may of been the source of many discs being warped, as they never spun true.Italic text


98. Remove axle stand and lower jack.

99. Tighten wheel nuts.

Bedding in process

Wilwood brake conversion (15” kit).

(Compiled using direct plagiarism by John_W from several posts on LotusElanCentral by ESM, Candles, Darren, John_W, Ailwyn, & Monty.)

(NB: most of this also applies to the 16” kit. Somebody who has fitted the 16” kit will need to highlight the differences.

This (in Elan terms) is a simple job. The reason it is easy is that the kit has been specifically designed by enthusiasts, not just a company mass producing a kit to fit many cars. It goes on easily, looks great and stops the car very well indeed. Maintenance is much reduced compared with standard brakes (see “maintenance” below).

With the provided hoses, connectors, brackets and fasteners the new brakes go on with no grinding, sawing, fabrication or other general mucking about. The calipers are beautifully engineered and the brackets and bells more so.

Tools required:

  • Spanners:10, 11, 17, 18mm.
  • If the old flexible pipe has corroded onto the hard-pipe, you may require a brake pipe spanner or 'crows foot' socket to undo the joint.
  • torque wrench
  • loctite
  • cable ties
  • jack
  • axle stands
  • hexagonal-head sockets (like an allen-key, but stronger): 10mm, 8mm.
  • 1/4" spanner is required to bleed the Wilwood calipers.

The 15" kit comprises:

  • 2 custom brackets (Brian MDB)
  • 2 custom hats (Brian MDB)
  • 2 plain vented discs 280x20mm (Wilwood, ex Rally Design - Rally Design Part No. 160-5840)
  • 2 Wilwood 4-pot calipers (ex Rally Design, Powerlite 1.38" 35.1mm, no dust seals - Rally Design Part No. 120-8729)
  • 1 set "Smart Pad" BP-10 (Rally Design Part no. 150-8813K)
  • 2 hoses to fit (Brian MDB).
  • 4 M12 bolts, 35mm, 1.5 pitch, class 12.9. (bracket to hub carrier)
  • 4 M10 socket cap bolts, 50mm, 1.5 pitch, class 12.9 (caliper to bracket)
  • 12 M8 x 25mm low-profile socket-head class G10.9 e.g from fastfixdirect (hat to rotor)
  • 12 M8, class10, all metal, zinc plated, self locking nuts (eg Philidas mk5, as used by AP Racing with their hats & discs.)

The M8 bolts have to be low head bolts to clear the caliper mount by around 2mm, and no washer is to be used under the head for clearance reasons.


  1. Lay out all the bits somewhere clean, dry and warm. De-grease the discs (rotors). Test assemble the bits finger tight. Lacquer the aluminium bells and the iron discs (rotors) to prevent corrosion where they are in contact.
  2. Assemble the hats to the discs (rotors) using bolts of the correct grade and head thickness, and use a torque wrench. Bell to disc bolts should be torqued to 20nm, using loctite. The hat sits outside the disc. The nut MUST be on the hat face and visible through the wheels' spokes. ONLY use the correct grade of fasteners to mount the disc to the hat and DO NOT use washers under the bolt head (clearance is minimal).
  3. Lacquer the assembly to prevent/delay corrosion (not the friction faces of the discs, obviously).

Disc hat.jpg

Disassembly: Dismantle the old system in the obvious fashion.

  1. Use the 10mm hexagonal socket to remove the caliper mounting bolts.
  2. Remove the wheel-arch liners for good access and optimum positioning of spanners on the joint between the flexible pipe and hard-pipe. (Liner removal is an adventure in itself if your bolts have rusted, and you might be lucky and be able to do the job with liners in situ, but you might just damage the hard-pipe because of poor access. With the liners out, you can also clean, repaint and waxoyl everything in the region.)
  3. Remove the spring clip plate holding the metal end of the flexible hose onto the bracket on the chassis.
  4. The middle mount on the hose can be quite hard to get apart (rusted clips). If you need to cut through the old clip with a Dremel, obviously cut the clip where it overlaps the gap in the mount.
  5. The worst job is undoing the brake union between the flexible pipe and the hard-pipe. This is a standard right-hand thread (metric). Soak the area in releasing fluid a few days before taking it apart to help you avoid shredding a union. The mount on which the hose meets the hard pipe is probably going to be covered in crud. Before detaching the hose from the hard-pipe clean all loose corrosion/debris/crap from the area otherwise it might drop into the end of the new hose when you fit it, and clean up the hard-pipe to help in undoing the end union. Have a clean piece of paper towel handy to wrap the end in when you've undone it (slows fluid loss and keeps it clean). To undo the old hose from the hard pipe use a proper 11mm brake-pipe ring spanner or a crows-foot socket. (Note: mine didn't shift even after that lot, so I had to use vise-grips.) The end-union must unscrew freely without twisting the metal pipe. There is a risk of twisting the hard-pipe if it has become corroded/fused to the pipe, therefore the best method is to loosen this union initially by turning the 19mm spanner on the hose fitting while keeping the 11mm spanner static. This way you won't knacker the hard pipe whatever happens. If the nut is loose on the pipe you're laughing; if not then its more fiddly spinning the hose but no real bother. You’ll need a drip tray to catch the brake fluid, but you don’t need to have drained the system beforehand. If all else fails, just accept that you will have to replace the hard pipe to the master cylinder. The LHS (passenger side) looks a real pig and I would try everything to avoid replacing it, but the RHS (drivers side) only took me about an hour to replace.


  1. Have a really good clean up. As a minimum concentrate on the hard-pipe/flexible pipe joint, the hub, and the face of the hub carrier where the brackets mate.
  2. Clean up the mount for the hard-pipe/flexible pipe joint, making sure the end of the hard pipe does not get dirty (cover in foil/paper towel.
  3. After removing the old caliper and disc from their mounts check the new aluminium caliper bracket against the hub. Give a real good clean to the surface of the hub where the new aluminium mount will go, so that it will sit nice and flat on it. If necessary, wire brush it, gave it a quick file and offer up the aluminium mount to ensure all looks well before fitting it.
  4. The original caliper-mounting bolts don't quite reach the end of the holes in the hub carrier, so the end of the female thread there is generally full of crud. Put in one the mounting bolts, from the normal side, and tighten it until you reach the crud then tighten and loosen in turn until you have cleaned the thread out. This ensures the new bolts will tighten onto the mount and not the crud. If you can't get the old disc off then doing this will allow you get the bolt through the mount and jack off the old disc (a trick worth knowing). If you use WD40 to help out here remember to degrease the threads thoroughly before fitting the mount at it changes the tightening torque required and stops loctite working.


  1. Seal up the “L-bend” caliper end of the new hose (foil is ok) so fluid doesn't leak out when the other end is attached then withdraw the towel from the end of the hard-pipe and attach the new hose. The thread on the end of the new flexible hose which joins onto the hard-pipe is the same as the one which you have removed, and is just a standard metric thread.
  2. Attach the other end of the flexible hose to the caliper. (The old standard flexible brake hoses will not fit the Wilwood calipers which do not use banjo bolts.) The flexible pipes supplied with Brian’s kit have an “L-bend” end which screws into the calipers, rather than the “banjo bolt” of the standard calipers. This “L-bend” has a 1/8-27 NPT tapered thread which should only be tightened into the caliper to about 3.3 FT/LB (4.5 N-m). This is barely more than finger tight! It does not screw all the way into the caliper or anywhere near to the bottom of its thread. Fit the clip to the hose/hard-pipe union bracket by tapping the back of it gently to force it home.
  3. Remember to install the disc before the caliper. You can even put the pads in just before attaching the caliper to make alignment nice and easy (it’s easy enough to insert the pads afterwards too). Obviously the disc must be well degreased before it comes into contact with the pads.
  4. Attach the aluminium mounting bracket to the hub carrier using the 10mm hexagonal socket on the bolts and torque to 80nm. The lightening pocket faces the car's centreline.

For Brian's early kits the machined recess is to the disc side, this allows for bolt clearance. see the image in the document that illustrates this' textrear

Attach the caliper to its mount using the 8mm hexagonal socket on the bolts and torque to 65nm. Use loctite on all fasteners. When attaching the caliper, ensure the brake hose will lie where required and is not twisted.

  1. Point the brake pipe connector “L-bend” upwards, not vertical but raked slightly towards the rear of the car, and only torque them to 4.5nm. The angle of the right-angled brake union on the caliper is important. It should be adjusted by screwing the union in or out a few degrees to allow the hose to run close to the upper wishbone arm and out of the way of the wheel rim (see Darren’s photo). If the brake union points vertically up it will direct the hose to rub on the wheel rim.
  2. Pull the right amount of hose through to the outside of the middle attachment to allow sufficient for full lock (away) and full suspension extension. Ensure too much hose isn't pulled through or it will rub on the wheel. Now cable tie around the pipe to hold it tight and prevent it gradually sliding through the middle union.
  3. Check all the unions are tight then bleed the brakes.
    Hub caliper mount.jpg    Darren brakes.jpg

Brake bleeding: Bleeding is very easy with the Wilwoods, especially if you have only replaced the front brakes and not disturbed the rear system. There is a plethora of brake-bleeding advice on LEC for difficult cases, so this addresses the simple case only.

  1. You will need a 1/4” ring spanner suitable for the tiny bleed screws.
  2. Fill the reservoir, then bleed using your preferred method starting from the caliper furthest away from the master cylinder. (I replaced all the fluid at this time, so bled the rear brakes also.)
  3. I used a pressure bleeder and bled each of the four nipples on each caliper, upper ones last. However note that some of the Wilwood calipers have a tag attached which reads “For proper bleeding, bleed screws must be pointing up”, and the Rally Design website for the Dynalite 4-Pot caliper says “caliper is to be bled by releasing the top two bleed nipples only” (this is a slightly different caliper but the principle should be the same). Rally Design.
  4. I'm surprised that there's no rubber dust/crap covers supplied for the nipples, so it may be an idea to buy some.

Important Checks (before driving the car):

  1. After bleeding, press the brake pedal a few times to ensure it’s firm then check for any leaks of hydraulic fluid. I don’t mean puddles on the floor – I mean while the wheels are off looking for any weeping of fluid.
  2. Put the wheels on and test-spin the wheel after you've assembled it all to make sure nothing rubs. If it does, adjust the hoses, “L-bend” union and tie-wraps.
  3. Then jack the car down and drive a few feet in a quiet place with the hood down to ensure you can hear if anything's rubbing with the suspension under load. Don't drive more than a few feet if you hear a rubbing noise. Fix the clearance and test again.
  4. If you're happy nothing's rubbing, go for a quick spin, then come back, remove the wheels and check the braided hoses again for any wear to ensure there's nothing been rubbing on them. Note that several people have experienced damage to their nice new brake hoses owing to maladjustment. If the brake hoses rub through, this will cause brake failure. Do the checks.

Bedding the brakes:

See the Wilwood website 'bedding' article at .

Fitment Comments:

  1. Be very careful when routing the new braided hoses, making sure they do not rub on anything, especially anything which rotates. I found it best to have the loop in the hose angled back towards the wishbone, thus giving maximum clearance to the wheel.
  2. Even after thorough bleeding, the brakes do not give full “feel” through the pedal until after the bedding-in procedure, and may take ten miles or so of driving to firm-up the pedal and achieve their ultimate state.
  3. The brakes buzz a bit on medium to heavy braking (maybe the pads resonating), but its not a problem and just sounds like the brakes biting and doing their job.
  4. Some people have reported a slight creaking sound if the brake pedal is pressed hard when stationary with the engine off in a quiet spot (not heard at any other time). It’s not known what it is, but it doesn't affect the stopping power. Note that this is not the clicking sound mentioned under “maintenance” below.
  5. see here for friction material applicable to both the Powerlite 1.38" 4-pots used in the ESM/BrianMDB 15" kit and the Dynalite 4-pot calipers used in their 16" kit. (I think most people went for the 'Smartpads' at about £20 a set from Rally Design ; just to be different Monty has 'Poly-Q' and seems to like them. Friction vs temperature graphs can be found here .


  1. The 15” Wilwood set-up uses calipers without dust-seals. This means that care has to be taken to clean the pistons before pressing them back into the caliper, e.g. when replacing pads.
  2. A healthy amount of copper slip around the pistons makes a decent surrogate for dust seals and should mitigate the piston slip-sticking problem described below. Just slop a load on the back of the pads at every service (that generally happens anyway to some extent to stop squeal) and once the pistons are protruding a reasonable amount actively coat them with it. Its remarkably tenacious.
  3. A clicking noise from the Wilwoods has been reported after a couple of winters’ use, which is due to slip-stick of one or more pistons (moving in steps instead of smoothly and bashing the back of the pads when they unstick and move - hence the noise). The solution is cleaning the pistons, as below. The noise becomes noticeable on brake application when stationary or very low speeds and is completely unnoticeable on the move at any significant speed, and brake performance remains good.
  4. ESM’s recommended clean-up method is to unbolt the caliper, stick a bit of wood in-between the pots so they don't come all the way out and pump the brake pedal until all the pistons move out far enough to show clean metal (it is obvious which ones are sticky as they come out after the free ones hit the wood). Then use brake cleaner and metal polish to clean the crud off. Its difficult where the clearances are small to the caliper body but a 'flossing' with a cloth and using a plastic glue mixer as a scraper works (don't use anything that will score the piston). Then spray the piston lightly with WD40, lever them back in with the bit of wood and re-assemble. The clicking noise will now be gone completely. Allow about 45 minutes a side (you probably won't need that long though). If you have let it go such that pitting/corrosion is a problem, replacement pistons are listed at about £6.50 each on Rally Design.
  5. The Powerlite calipers have aluminium pistons, so tend to corrode in harsh Winter environments, but can be replaced (see above).
  6. When renewing discs, remember to re-lacquer/paint between the aluminium hats and iron discs to prevent pitting on the face of the aluminium hat where it mates with the disc, owing to galvanic corrosion.
  7. If you get your wheels balanced, recheck for adequate clearance of the hoses. The plastic sheathing of one of my hoses was nicked by wheel balance weights.


see Philbo



(This is a reproduction of Bob's instructions sent out with the conversion kit - less photos at present)

Tools Required

10mm Hex Head (Allen Key) socket

8mm Hex Head (Allen Key) socket

Suitable Torque Wrench

14mm Socket/Spanner

Phillips Head Screwdriver

Time to complete Once the old brakes are removed this is around a half day job for a general car DIYer, however be prepared to leave extra time – don’t rush working on the brakes! If you are not confident with working on the braking system then please leave it to a professional – the value of your life far exceeds any bill.

Instructions The following instructions assume that you’ll be replacing the brake fluid at the same time as upgrading the brakes, fluid needs to be changed every 2 years regardless of mileage.

1. Loosen the wheel nuts one to two turns are plenty

2. Jack up the car and place on axle stands


3. Remove both wheels

4. Loosen the cover on the brake fluid reservoir

The following instructions cover the steps to do one side

5. Carefully remove the banjo bolt/brake hose from the caliper

6. Allow brake fluid to drain out of the system into a suitable container, do not allow brake fluid to come into contact with painted areas, avoid all contact if possible – it’s not nice stuff.


7. Remove the existing caliper (refer to the manual)

8. Place the bolts that mount the caliper in a safe place – they will be required later.

9. Remove the keep screw from the disk – if it’s been there a while then it’ll probably be difficult to remove. (Philips Screwdriver) May require impact wrench

10. Remove the disk from the hub, will probably require a fair amount of persuasion if it’s been there a while, but it will pull free.

We have now stripped the old brakes and are ready to start fitting the new

11. Rub the hub surfaces and the caliper bracket mounting with wet & dry sandpaper to remove any debris and ensure the surface is completely smooth and flat.


12. Place an M12 safety washer onto the OEM caliper mounting bolt (so that when fitted the washer is between the head of the bolt and the caliper bracket.

13. Fit the caliper bracket to the car using the OEM caliper mounting bolts, the flat caliper mounting face should face the front of the car and the bolts heads should sink into the recess in the bracket. Torque: 70 ft/lbs

14. Slide the spigot ring onto the hub, the upright of the ring should fit snugly to the hub.

15. Slide the disk onto the hub, align the disk so that all four bolt holes on the hub are square with the bolt holes on the disk (where a 5 hole disk has been re-drilled you need to check the alignment carefully).

16. Secure the disk with the keep screw, tighten just enough to hold the disk against the hub and ensure the disc is true to the hub face.

17. Place the safety washer on the caliper bolt so that when fitted it sits between the bolts head and the caliper body.

18. Mount the caliper to the bracket. Torque: 35 ft/lbs

19. Remove the cover from the brake pipe connector on the caliper

20. Fit the brake hose to the caliper using the supplied banjo bolt and washers. Hand tighten the banjo bolt and use a 14mm spanner to pinch it tight, max torque 20 ft/lbs.

DO NOT OVER TIGHTEN THE BANJO BOLT – YOU WILL SNAP IT you may also damage the caliper by stripping the threads in the caliper.

A copper washer should be present on both sides of the hose connector i.e. Banjo Bolt – Copper Washer – Brake Hose – Copper Washer – Caliper

21. Get a friend/wife/neighbour to turn the steering from full lock to full lock while you ensure that the brake hose does not rub and is not over stretched at any point. Do this several times to ensure clearance.

22. Remove the R-clips from the pad retaining pins and remove the pins from the caliper.

23. Slide the pads into the caliper

24. Clip an anti-squeal spring onto each pad

25. Refit the retaining pins, ensuring that the anti-squeal springs go underneath the pins (use a small screwdriver to press the spring arm down whilst inserting the pin).

26. Refit the R-clips to the retaining pin between the caliper body and the pad (small recesses for the R-clips can be seen in the caliper body). This will require adjustment of the positioning of the retaining pins.


27. Refill the system with brake fluid

28. Look for any signs of leakage, particularly at the caliper to hose mounting and the hose to pipe joint at the top of the wheel arch (in case it’s been disturbed).

29. Bleed the system properly (all four wheels)

30. Check again for any leakage

31. Refit wheels.

32. Check (as per 21) for any signs of interference between the brake hose and suspension components or wheel – you need to be under the car to see properly

33. Place the car back on the ground

34. Check for a firm pedal

35. Start the car and check (at very low speed) the pedal operation, if not OK go back to 29

36. Go for a gentle run to check brake operation, if not OK go back to 29

37. Place car back on axle stands and check for any leaks (as 30) or hose clearance issues (as 32/21)

38. Follow any instructions for bedding in the pads

39. Return car to the road ☺

Hints & Tips

• New OEM caliper bolts can be had (in the UK) from your local Vauxhall dealer (see the forum cross reference section for details)

• While everything is stripped away, take the opportunity to treat any suspension parts or areas of the chassis that are rusting.


see LGM



Darren's solution


see Algirdas