TR6 – TR4A Rear Braking Components
All the rear braking components are the same on 68 – 76 TR6 and TR250s. TR4As with IRS share these components as well.
Overhauling your rear brakes makes a nice project. Chances are that the rear brakes on your TR’ are a rusty mess-not too dissimilar from the picture below!
Rear brakes fail slowly, over a long period. While a brake fluid leak will be immediately obvious, other things may not be:
If the brake adjuster becomes seized, and the shoes wear down, you’ll have less and less braking happening at your rear wheels. It will reach a point where almost all the braking is done up front.
Usually, this is accompanied by your emergency brakes not functioning either. This can be a serious issue…
One of the nicer things about TR6 rear brakes is the ease of access:
You jack up the car and support it on safety stands. You then remove the rear wheels. Take off the brake drums. This will entail the removal of two small screws and a little hammer tapping. Then you can unbolt and remove each half shaft and hub assembly. The whole assembly will slide out thru the big hole in the brake back plate.
You then disconnect the rear brake pipe to the wheel cylinder and the handbrake cable.
You can now slide each complete rear brake assembly off of the trailing arm mounting studs.
Here is what a typical TR6 rear brake looks like after removing the drum.
You can see the crusty wheel cylinder, dilapidated shoes and hardware, and the rusty backplate easily. You can’t see the seized adjuster on the bottom though.
Usually, all the brake parts are a filthy mess.
We have the necessary components in stock to properly restore/rebuild TR rear brakes.
To top it all off, the parts are really cheap!
About the only part that we don’t carry is the brake back plate itself. It is a heavy steel stamping. It is usually heavily rusted.
You can strip off the components and then have it bead blasted or dip stripped. Follow up with a nice paint job and you can start building your brake assemblies.
Here is a freshly blasted and painted back plate off my car!
Even though I sprayed “umpteen” coats of Black Krylon onto it, you can still see lots of pitting.
If you really want it perfect, you’ll need to use lots of high-fill primer before painting.
The first part of reassembly is also the easiest.
Bolt the brake adjuster onto the backplate. Take my advice and buy two new ones. Your old adjusters are probably seized!
Next, you need to install the wheel cylinder. The shank of the wheel cylinder fits into a rectangular slot in the backplate. Prior to installation, you must install the handbrake lever. This is one piece of hardware that you will probably be reusing.
You can see how the wheel cylinder and the brake lever are fitted together on the backplate.
Here is a picture of the other side-just for clarity.
Now the “Fun” begins…
You need to install the steel spring plates and the rubber-sealing boot. These clips hold the wheel cylinder tightly onto the backplate, but they allow the wheel cylinder to slide sideways in its mounting slot.
This picture shows the inner most clip on the wheel cylinder shank.
Pay attention to our mounting instructions for those wheel cylinder clips.
Installing the clips onto the wheel cylinder can be a Friggin nightmare. It isn’t too bad if you do it in the correct order.
The mounting slot in the shank of the wheel cylinder is a fairly roughcast surface. It may be necessary to run a small file down the length of the slot a few times just to clean things up. Just a couple of file strokes may be enough to allow for easier clip installation.
After installing the wheel cylinder and brake lever into their respective holes in the backplate, slide the rubber-sealing boot into position.
Next, install the middle sized spring clip-the one with the “hooks” on the end. This clip needs to be pushed in from the brake lever side. It should be pushed in with the “hooks” pointed up. Next, the large flat clip needs to be pushed in from the other side. This means that the hooks of the innermost spring clip will mate with the notches of the flat clip.
Following that, the small spring clip can be pushed in from the brake lever side. It will need to be “persuaded” into its final resting place with a hammer and a large slot screwdriver.
Here is a complete assembly. The clips are all fully seated and flat. The wheel cylinder rubber boot is nicely positioned and not all “scrunched up”.
The brake shoes and springs can now be installed.
The rear wheel cylinder is uppermost and the brake adjuster is at the bottom.
There are two shoe return springs. Both springs are mounted underneath the shoes-that is to say that the springs are mounted on the backside of the shoes.
The longer spring, with two coils, is the upper spring. The other spring, with one long coil, is the lower spring. Assemble the springs into their retaining holes in the brake shoes. With someone holding the backplate firmly on a workbench, you can muscle the two shoes, complete with springs, into position. You’ll need to first manipulate the rectangular shoe hole over the handbrake lever and into its slot in the wheel cylinder. The other end of that shoe can be positioned into the brake adjuster slot. Then it is simply a matter of stretching the springs and pulling the other shoe into position.
Following that, the shoe hold-down hardware can be installed. Needless to say, I would always recommend new springs and hold-downs. The old ones are bound to be rusty!
The hold down hardware is really easy. Simply insert the clevis pins into the holes in the backplate and then thru the shoe holes. While holding the clevis pin with one hand, push down and turn the spring loaded securing clip with your other hand.
At this point, the brake assembly is ready for installation onto the car.
A couple of pointers though:
-Six studs and nuts secure the brake backplate, and the rear wheel hub and bearing unit onto the trailing arm face. These studs are threaded directly into the soft Aluminum trailing arm. They are easily stripped. If the studs fall out, think about the rear wheel and brake assembly falling off of your car! Check all six stud holes. If any of the threads are stripped, have a machine shop install HeliCoil thread inserts. The torque specification on the trailing arm studs and nuts is only twelve foot-pounds. If you over tighten the nuts even a little, you’ll probably strip the threads. Use a torque wrench…
-Chances are that the rear brake piping is badly rusted. It almost always needs to be replaced.
Unfortunately, you cannot purchase pre-bent piping for these cars. Either you can make up your own pipes (if you possess a proper double-flaring tool and are proficient at using it), or you can buy a brake pipe kit. We now have copper brake pipe kits in stock for all 72 – 76 cars. These kits include the rear brake pipes (the ones on the trailing arms that connect the rear wheel cylinders to the flex hoses. They come supplied in the correct lengths, pre-flared, with fittings attached. They still need to be carefully bent into shape though.
-This is a good time to service your handbrake as well. It probably means that you should install new brake cables. Your old cables are probably stretched from years of use. Badly stretched cables will exceed the “throw” of your brake lever.
-Your old brake drums are probably rusty and oversized. Do yourself a favour and install brand new drums, especially since we have them on sale now.
Here is a freshly assembled rear brake. Yours can look this nice too…
This picture shows the proper orientation of the return springs.
The piece broken out around the bleed screw is not a rarity. I’ve seen this on several TR6s. It is dangerous. That bleed screw is so close to leaking that it isn’t funny.
The Alloy casting on these cylinders is fragile. Over tightening the bleed screw puts too much stress on the thin section of the wheel cylinder shank.
TR6 – TR250 – TR4 Rear Brake Parts
A Typical TR6 Wheel Cylinder
Note the corrosion & pitting inside.
This cylinder is not suitable for overhaul!
TR6 – TR4 – TR3A Rear Wheel Cylinder
Correct for 1962 TR4 thru 1976 TR6. Makes a sensible low-cost substitute for TR3As.
.700” bore size.
We are offering a quality, European made, Lockheed brand cylinder. Others may be supplying wheel cylinders from “Who Knows Where”.
Brand new cylinder, complete with bleed screw.
TR6 – TR250 – TR4 Wheel Cylinder Repair Kit
When brand new wheel cylinders are on sale for twenty-six bucks I question the merit of rebuilding your old cylinders-except for one thing…
If your old cylinders have decent internal working surfaces, you can install a seal kit without taking the cylinders off of the back plate. Removing and reinstalling those wheel cylinder mounting clips is a nuisance.
If you want to try and overhaul your old wheel cylinders, here is the kit.
It includes the piston seals, end boots, boot retainer clips, and bleed screw rubber caps for rebuilding both rear cylinders. Fits all standard size .700” cylinders.
Wheel Cylinder Mounting Hardware
Just like the wheel cylinder cylinders themselves, the mounting hardware is interchangeable from 1958-1976. There is a combination of three interlocking steel plates, which hold the “shank” of the wheel cylinder onto the brake back plate. This complicated arrangement is necessary so that the wheel cylinder is held firmly onto the back plate, but at the same time is able to slide back and forth in the back plate slot.
In addition to the three locking plates there is a rubber-sealing boot.
All of these items deteriorate or rust away and should be replaced at the same time as the wheel cylinders.
Take careful note of the positioning of the steel clips before removal. This will allow you to install new ones in the correct location and order.
Includes all the mounting plates & rubber boots to mount both rear wheel cylinders.
TRW and Lucas has discontinued this item. We finally have aftermarket kits available. Fits 1957-1976 cars. Includes enough parts to mount both rear wheel cylinders.
TR6 – TR250 – TR4A IRS Rear Brake Hoses
One hose connects the chassis to each trailing arm.
Fits all 68-76 TR6-TR250.
Fits TR4A or TR4 when fitted with independent rear suspension.
LH Hose HO-BRREA-BH110
RH Hose HO-BRREA-BH131
TR6 TR4 Rear Brake Adjuster
These adjusters are almost always seized solid.
Do you get the feeling that your TR’s brakes aren’t as effective as they once were?
It’s possible that the rear adjusters are “not adjusted”.
Very commonly you will find that the adjusters are totally seized up. Consequently, even with the brake pedal pushed down as far as it will go, the brake shoes barely contact the drums! In this condition the brakes won’t do much stopping.
The only solution is to free up the adjusters so that the slack can be removed from the rear brakes.
The adjusters are easily removed from the back plates after removing your drums.
They are secured to the brake back plates with two threaded studs and nuts. Undo the nuts, remove the shoes, and then the adjusters can be slid out.
Adjusters used to be pretty damn expensive. Lucas-Girling-TRW or whoever they are, made adjusters real expensive in the last couple of years.
XRN Engineering just got good quality reproductions done. They look every bit as good as the originals to me….yet they are about half price!
Now with sensibly priced adjusters available, it’s hard to justify screwing around with the old ones.
Easy on the budget and simple to install, now that’s something that I like!
We have new adjuster units on sale.
Fits all TR6 – TR4 1962-1976.
Fits LH or RH.
TR6 – TR250 – TR4 – TR3A Rear Brake Shoe Set
Includes 4 shoes to service both rear wheels.
Fits all TR4 though TR6. Fits TR3A from approximately 1960 on.
TR6 – TR4 Rear Brake Shoe Hold Down Kit
Includes the clevis pins and spring clips that hold the brake shoes against the back plates.
TR6 – TR4 Brake Shoe Return Spring Kit
The rear brake return springs are gettin’ pretty darn rusty on most cars these days! In the past we haven’t had any new ones. All we could do was scab decent used springs off of our parts cars. We now have brand new springs available at a sensible price.
Kit includes upper & lower springs for both rear wheels.
Fits all TR6 TR250 TR4A. Fits later TR4 with 9” brakes. DOES NOT include shoe hold down hardware. (Listed above).
These screws are often missing or damaged. Most cars need 2 screws per drum.
Typically, the necessary screws are ¼” X 28 (fine) thread, countersink head, star drive, and about ½” long.
We are now able to offer these in stainless steel with a slot drive. You will appreciate the fact that they are stainless about a year from now, when you need to remove them!
Fits TR6-Spitfire-GT6-MGB-Midget, and probably many others.
TR6 Brake Drums (also TR4A IRS &TR250)
I can tell you from my thirty years of TR6 experience that most cars need new drums by now.
Usually, when you pull off a TR6 drum, it will be accompanied by copious quantities of rust and brake dust.
Brake drums are machined cast iron. In most cases they aren’t even painted on the outside. This makes for a rusty mess.
Most cars spend the entire winter season in the garage. This means that any moisture in the rear brakes will cause serious rusting of the brake shoe facing in the brake drums. Inevitably this results in deep rust pitting. Since TR6 drums were never very cheap, you can bet that your existing drums have been turned enough times that they’re past their safe wear limit.
We got a small number of brand new drums at a great price.
Here’s your chance to get new drums for about 40% off-but only while they last!
Fits any 68-76 TR6 – TR250 or TR4A with IRS.
TR6 – TR4A Handbrake Cables
The hand brake on your TR’ is an important safety component! Triumph hand brakes only work so-so at the best of times. Although the hand brake is often ignored, its importance becomes very apparent when your hydraulic brakes suddenly fail. Hand brakes fail because the cables have either seized solid, or they have stretched a lot. If the cables have seized, you’ll notice that it is no longer possible to pull up the brake lever.
With badly stretched cables, pulling the brake lever up as far as it will go will not be enough to operate the rear brakes. The “stroke” of the hand brake lever is actually very short. The amount of braking will be minimal and often the hand brake won’t stop the car from rolling.
Replacement with new cables and then adjusting them up will solve this.
Fits all TR6 & TR250. Fits TR4 & TR4A when equipped with I.R.S. (independent rear suspension).
2 needed per car.