Triumph TR7 rear disk brake conversion - Grubbymechanic shorts.

In this video I convert the rear brakes on my Triumph TR7 from drums to discs, I look at the costs and benefits of making the change.

[@peepachu]

I wish there more people like you out there working to keep those beauties on the road. Thank you sir!

[@michaelkip3787]

Great job Mr Grubby :)) I did much the same but 3 different iterations. 2 with the MGF calipers which work great with the handbrake mechanism and 1 set using a VW golf caliper and a cobbled up handbrake set up. 1 set I used MGF rotors with the MGF calipers as you have done , the other MGF calipers with BMW E30 rotors and the other with E39 rotors as the 1st attempt. I made my own brackets to suit and now you have me enthused about doing a follow up video of my initial attempts to show how they turned out. Again great job and well done. Michael Kip

[@bmwcarrmann429]

Hello sir back in the day after we put the Buick grand national Normal aspirated engine in dadn blew up the triumph diff here in America so he bought a chevy SS Montecarlo differential it eas aninch wider but he took all of the mounting brackets from the triumph diffmounting and it wasn5 lug nut rear wheels and it worked and the hand brake and everything he made to work and it works great its like a 3.05 gear ratio and the turbo 350 transmission my dad built and it's geared great as a matter of fact it's a you can't grab the thousand dollars off the dash board type of car now my younger brother is the caretaker of the car I love you'll build on all things you've done mate enjoy and keep making great videos I'm disabled with long haulers covid and I want one of these sooo bad to make mine eve his color choice is two tone blue like yours

[@briancolin4014]

Currently in search of a new differential for my 76’ tr7 4speed, a,ready took it all apart and seeing this helps because now i can swap and upgrade to discs, thank you

[@clivewilliams3661]

There are a number of considerations with the disc brake conversion: 1) A drum brake is mechanically more efficient at gripping the wheel than a disc brake, that is why the likes of Mercedes, BMW, Porsche and Opel fit disc brakes for the main service brakes and use the drum (usually the top hat section of the disc) for the parking/emergency brake. With a front engine and rear wheel drive the rear brakes have much less work to do and so can tolerate drums on the rear because they don't heat up as much. I have never had brake fade on rear drums, only front even in competition. 2) The vehicle brake balance is critical to the safe performance of the vehicle and with a bespoke system fine tuning of the balance is necessary. Whilst this can be calculated and the appropriate master cylinder can be selected this still requires further fine tuning. The pressure limiting valve proposed for the rear is just that i.e. it limits the maximum rear brake pressure not the proportional split between the front and rear, that can only be done at the master cylinder, preferably by the use of a balance bar and twin cylinders. Note that any adjustment of the brake pressure within reach of the driver is contrary to C&U regs although in my experience most MOT guys either don't know what it is or ignore it, but then a VOSA road side stop......... 3) Single pot calipers with a handbrake mech are the worst of two worlds a) they operate on the disc that is not as good as a drum and b) The single pot sliding caliper has poor performance relying on the casting strength to pull the second pad into the disc after the first pad has made contact, wearing one pad first, they are also prone to seizing, giving poor performance. I have had some standard systems that required frequent attention to ensure that the calipers were sliding on the pins to give just the adequate performance. Most performance cars use horizontally opposed piston calipers. Single/two pot sliding calipers are manufactured for one reason alone - they are cheap! 4) Disc brake parking brakes have a reputation for relaxing pressure when applied to a very hot disc and then cooling. This ought to be overcome by applying the parking brake very firmly but this does not happen on occasions. My wife parked our Skoda Octavia (VAG brakes) on a sloping road next to a junction and when she returned the car had rolled across the junction and nearly down into the property opposite - she swears she set the handbrake properly. Chrysler Voyagers had this very issue and were subject to a redesign following many accidents. Our current car (VAG) has an electronic parking brake and the handbook specifically recommends leaving the car in gear on a slope as the grip on the rear disc relaxes when cooled. 5) Reducing the rear drive flange diameter should be carried out on a lathe. The system of using an angle grinder can't ensure that the flange/axle remains in balance and given the location it will be the bearings that will suffer due to the harmonics.

[@bmwcarrmann429]

Yes it's worth it my dad worked on his 14.5 years the first time of his rebuild

[@wayne975]

I am hoping to buy a 1980 SA model soon. Thanks for the input.

[@bmwcarrmann429]

This car is a great car to modify and make it look so good and perform great I just wish B/L WOULd have held on a little long and built more of them

[@bryan26762]

Accident waiting to happen !! You've connected the floating callipers using a solid copper pipe. Eventually the copper brake pipe is going to work harden and fracture resulting in no brakes !!

[@flybobbie1449]

Brakes on my old TR7 in the eighties were dreadful. Only time i ever locked them up was on my driving test. I was replacing the lip seals in the master cylinder every 6 months as a i couldn't afford a new cylinder back then.

[@mrcard69]

Nice video. Any info on where you purchased the kit? Would also be really helpful to know the MGF part numbers.

[@grubbymechanic]

I deliberately didn't mention the supplier of the kit as I didn't feel it was that great, the service was pretty poor and the quality was a bit low, nothing insurmountable but it definitely wasn't "bolt on". . There is only one type of brake set up for the back of the mgf/ mgtf so you can't get the parts wrong.

[@dylansedgwick2932]

@@grubbymechanic still would be interested in knowing what kit you used