Richard71 Posted July 28, 2020 Report Share Posted July 28, 2020 Hello All, I've just finished a brake upgrade (downgrade?) on all four corners of my TR6, Wilwood calipers, Wilwood pads, new discs all round, original servo & master cylinder re-fitted after having them both reconditioned by Past Parts. The brake pedal is firm with no excessive travel, the car stops, but nowhere near as satisfactorily as with the standard set-up, a longer stopping distance is required. I've only covered 25 miles with the new brakes and drove it normally, not following any particular bedding-in procedure. I felt more comfortable with the standard brakes, but being a sucker for the "bling factor" I went for this Wilwood set-up and they do look good, but won't look very happy if the nose of the car is jammed under a bus! My question to the collective is, how imperative is it to follow a "bedding-in" procedure??? I've changed discs & pads (at the same time) on cars before and simply drove the vehicle normally without any adverse effect. Richard. Quote Link to post Share on other sites
jerrytr5 Posted July 28, 2020 Report Share Posted July 28, 2020 It is important to bed in the brakes, but what type of pads have you installed? If they are race pads they won't work until they're hot anyway. Jerry Quote Link to post Share on other sites
john.r.davies Posted July 28, 2020 Report Share Posted July 28, 2020 All "bedding-in" does is the heat the pads to the highest temp they will face in use, to condition them and drive off any residual volatiles. It's nothing to do with conforming them to the worn discs, which you don't have anyway. Worth doing nonetheless. More likely, did you clean off any preservative coating on the discs? They are cast iron, and will rust away in store unless protected, and some oily substance is probable. No point in cleaning the discs, that will have scraped off onto the pads by now, but they may be a tad slippery! But maybe clean them anyway, with brake cleaner, ditto the pads and take a rasp to those. to remoeve the surafce layer Then go out and find a safe piece of road , and do a proper bed-in. Stand it on it's nose! That, with luck, will remove/burn off any residual preservative. If no improvement, new pads then. Also, when you bought the calipers, did you tell them that the master cylinder would be the original? If the diameter of the new pistons is greater than the old, then you ned more foot pressure for the same squeeze of the pads. Jerry got in front of me about pad spec. Good point! Good luck! John Quote Link to post Share on other sites
Richard71 Posted July 28, 2020 Author Report Share Posted July 28, 2020 (edited) Thanks Gents, I cleaned the discs with brake cleaner before fitting. The pads are described as "street use" not "race", I'll give the discs another wipe down with brake cleaner and rough up the pads with a file/rasp and try again, this time following a recognised bed-in procedure. Will report back! Thanks again, Richard. P.S. Re the master cylinder, I conferred with Richard Good (Goodparts) on this wee project, it was never suggested that m/c and piston diameter may conflict. Edited July 28, 2020 by Richard71 Additional Info Quote Link to post Share on other sites
john.r.davies Posted July 28, 2020 Report Share Posted July 28, 2020 The only remaining part to blame is the servo, which you have had serviced. Are you sure about that functioning well, vacuum connection and so on? Quote Link to post Share on other sites
ntc Posted July 28, 2020 Report Share Posted July 28, 2020 http://www.racetorations.co.uk/triumph-c56/tr2-c3/tr2-brakes-c30/racetorations-kit-residual-pressure-valve-p363 Quote Link to post Share on other sites
Richard71 Posted July 28, 2020 Author Report Share Posted July 28, 2020 19 minutes ago, john.r.davies said: The only remaining part to blame is the servo, which you have had serviced. Are you sure about that functioning well, vacuum connection and so on? Hmmm, I'll carry out the usual checks. 6 minutes ago, ntc said: http://www.racetorations.co.uk/triumph-c56/tr2-c3/tr2-brakes-c30/racetorations-kit-residual-pressure-valve-p363 This is a non standard braking system Neil, I'm not experiencing long pedal travel, pedal travel is absolutely fine. Richard. Quote Link to post Share on other sites
Geko Posted July 28, 2020 Report Share Posted July 28, 2020 For a new setup it takes a while before fully bedding-in that is until a heat-induced "film" builds up between the pads and the discs. It may take weeks depending on the usage but heat is the motto. Quote Link to post Share on other sites
John Morrison Posted July 28, 2020 Report Share Posted July 28, 2020 Procedure I've always used, albeit withstandard stuff, was to get up to 60ish, brake steadily to 20ish without locking the wheels, and repeat a total of half a dozen times. John. Quote Link to post Share on other sites
stuart Posted July 28, 2020 Report Share Posted July 28, 2020 What pads (make) are you using? Stuart. Quote Link to post Share on other sites
ianc Posted July 28, 2020 Report Share Posted July 28, 2020 You haven't stated the diameter of the pistons in the Wilwood calipers. If the new total piston area is smaller than before, then braking will be reduced for a given pedal pressure. Note: if the new caliper has two pistons each side, the area is the sum of the two. If total piston area has been increased, then braking effectiveness should be increased for a given pedal pressure, but your foot would have to travel a bit further in order to shift more fluid into the calipers. Ian Cornish Quote Link to post Share on other sites
Richard71 Posted July 30, 2020 Author Report Share Posted July 30, 2020 The rear calipers have two pistons and the fronts have four, all pistons are 1.38" diameter. The pads are Wilwood branded and described as for street use. Richard. Quote Link to post Share on other sites
john.r.davies Posted July 30, 2020 Report Share Posted July 30, 2020 Ahhhhhhhhhhhhhhhhh! You only said obliquely that you had fitted rear discs! A piston of 1.38" diameter is vastly greater that the diameter of the OE rear brake slave cylinder! The volume of brake fluid that must be displaced is therefore vastly greater,and without a larger Master cylinder, your brakes will feel weedy. I'm surprised that your suppliers didn't mention that, if you bought them as a set. Quote Link to post Share on other sites
ntc Posted July 30, 2020 Report Share Posted July 30, 2020 (edited) 31 minutes ago, john.r.davies said: Ahhhhhhhhhhhhhhhhh! You only said obliquely that you had fitted rear discs! A piston of 1.38" diameter is vastly greater that the diameter of the OE rear brake slave cylinder! The volume of brake fluid that must be displaced is therefore vastly greater,and without a larger Master cylinder, your brakes will feel weedy. I'm surprised that your suppliers didn't mention that, if you bought them as a set. That is why I posted a link read the whole the reason nowt to do with pedal travel Edited July 30, 2020 by ntc Quote Link to post Share on other sites
SpitFireSIX Posted July 30, 2020 Report Share Posted July 30, 2020 Hi, So you have fitted disks on four corners and new pads? Brake pedal pressure & travel is similar to before? I guess this means hydraulic area's are similar. Your old Pads, shoes, drums & disks felt better? Stopped quicker? See if you can get on a "brake" tester? Quote Link to post Share on other sites
Waldi Posted July 31, 2020 Report Share Posted July 31, 2020 Hi Richard, since you indicate there is more total piston area front and rear, but the pedal travel has not increased (remains good) the total force applied on the pads must be higher (with the same pedal force). And more effective brakes is what I would expect. Surprised the pedal travel has not increased btw. Maybe because the rear disk calipers “use” less oil than rear drum brakes? I would drive it a bit more (if safe), it may be due to wearing in. I overhauled my entire but standard system too (with the exception of the front pads which are Greenstuff) and have driven around 100 km’s since. Brakes passed our “MoT” but I cannot get them to block (scream). I have decided to drive some more before investigating changing anything. (Oh, the Greenstuff pads are my “bling” ). cheers, Waldi Quote Link to post Share on other sites
Andy Moltu Posted July 31, 2020 Report Share Posted July 31, 2020 The bedding in process does to an extent depend on the compound itself. Some benefit from repeated braking from progressively higher speeds to bake them evenly. Also it can be about the contact area of the pad wearing in to match the distortions caused by wear on a used disc but that shouldn't be an issue if you have put an all new set up on your car. Some don't - it's pretty rare on a new car to be given instructions on breaking in the pads. Not all break pads are the same. Fast road+ and race pads tend to be designed to operate well at higher temperatures but often feel wooden and relatively innefective when cold and only come into their own when properly warmed upto to temps that might mean a road pad might fade. What pads do you have fitted? I would steer clear of green snot my experiences with them were similar to fitting a set of Moprod pads to my Mum's Metro 35 years ago and having to swerve into the hard shoulder as they were utterly innefective. Quote Link to post Share on other sites
Waldi Posted July 31, 2020 Report Share Posted July 31, 2020 Hi Andy, I ordered the Greenstuff pads per the recommendations at that time, 4 -5 years ago. Currently Mintex 1144 is more favorite. But squealing is often mentioned too. My experience with the Greenstuff pads is just too limited to be considered. I will drive for several more hunderd km’s and see how it behaves then. Cheers, Waldi Quote Link to post Share on other sites
Richard71 Posted July 31, 2020 Author Report Share Posted July 31, 2020 Thanks for the informative replies gents. I'll put some more miles on the car but may also fit a master cylinder with a larger diameter as suggested by John. Does anyone know where I can buy such a thing and what size I should be looking for? Richard. Quote Link to post Share on other sites
Andy Moltu Posted July 31, 2020 Report Share Posted July 31, 2020 My experinces with Mintex 1144 are positive - good bite from cold and resistance to fade. Vastly better than Greenstuff. The other good ones are Hawke HP+ which again are a good fast road pad - less bite than the Mintex when cold but a little more fade resistant and a bit more controllable. However the Hawke are much more expensive as there are fewer people selling them and as such no competition over price. Lots of people sell the 1144s so a more competive price. got them on both my TRs and the Stag. Had the Hawkes in the 6 until they wore out and I fitted a vented disc kit (the type that used spacers in the standard calipers) That kit came with Greenstuff pads which were a monumental downgrade from the Hawkes, scarily so. Soon got changed for 1144s and been very pleased for a few years. I might be tempted to revert to Hawkes on the 6 (as it has the power to work the brakes far harder than the other two Triumps) when they need changing but it's a difficult call - sublte difference in characteristics and price make that a difficult choice. Quote Link to post Share on other sites
ianc Posted July 31, 2020 Report Share Posted July 31, 2020 If a master cylinder of larger diameter is fitted, the hydraulic pressure in the brake pipes will be REDUCED for a given pedal force, so the braking will be less effective - probably not what you want! With drum brakes at the rear, the shoes are pulled away from the inside of the drum when there is no pressure in the brake line. As soon as pressure is applied, the slave cylinders in the rear drum brakes have to push the shoes outwards to meet the inside of the drums. With discs at rear, the pads will not be drawn away from the discs, so as soon as pressure is applied to the brake pedal, the pads in the calipers will apply braking force to the discs - the pedal travel will be very little (just sufficient to close the valve in the master cylinder) and the pedal will feel firm. Ian Cornish Quote Link to post Share on other sites
Z320 Posted July 31, 2020 Report Share Posted July 31, 2020 Hi, 2 x 2 pistons diameter 1.38" have a "working surface" of about 1,928 mm², 2 x 1 original Girling piston diameter 54 mm has about 2.290 mm surface. So this 2 x 2 piston calipers brake 16% worse than the original Girling caliper. Very simple is: with the same diameter of the brake disc it is not fundamental possible to bring more "working surface" on the brake pads Quote Link to post Share on other sites
Waldi Posted July 31, 2020 Report Share Posted July 31, 2020 Hi Andy, I ordered the Greenstuff pads per the recommendations at that time, 4 -5 years ago. Currently Mintex 1144 is more favorite. But squealing And dusting is often mentioned too. My experience with the Greenstuff pads is just too limited to be considered at the moment. I will drive for several more hunderd km’s and see how it behaves then. Cheers, Waldi Quote Link to post Share on other sites
john.r.davies Posted July 31, 2020 Report Share Posted July 31, 2020 I'm happy to accept that quoted OE caliper piston diameter, Z320 , as I don't know any different. But I fear for your arithmetic. Girlings, @ 54mm diameter, FOUR of them, so working area 9160mm^2 Wilwood 4-pots @ 1.38" diam (35mm), Eight of them, so work.area 7697mm^2 But same difference and I was wrong - Richard has a smaller working area of brake pistons. So the effect of a given pressure in the master cylineder will be LESS on the disks. He needs (as Ian pointed out) a smaller master cylinder! So that the given pressure of his foot is concentrated into a smaller area of piston. Demon Tweeks (many other suppliers are available, usually for less!) offer three sizes of Girling master cylinder, 0.625, 0.7 and 0.75 inches in diameter. https://www.demon-tweeks.com/uk/girling-alloy-master-cylinder-with-integral-reservoir-249578/ Quote Link to post Share on other sites
stuart Posted July 31, 2020 Report Share Posted July 31, 2020 (edited) 12 minutes ago, john.r.davies said: Demon Tweeks (many other suppliers are available, usually for less!) offer three sizes of Girling master cylinder, 0.625, 0.7 and 0.75 inches in diameter. https://www.demon-tweeks.com/uk/girling-alloy-master-cylinder-with-integral-reservoir-249578/ Cant fit them to a 6 without a lot of changes. Stuart. Edited July 31, 2020 by stuart Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.