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Binding Brakes


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I've just got my TR2 on the road after 11 years and in doing so, have replaced the full braking system with new parts from Moss. It has TR2 front drums, however rear axle is the later Girling model from a TR3.

 

When you first set off, I have around 1 inch of travel at the brake pedal. After around 3 miles of normal use, this decreases to next to nothing. After 5 miles the brakes are seriously binding, forcing me to stop as the engine is quite unhappy.,

 

All the wheels are locked at this point, the rears are almost impossible to move, the fronts are tough to move, but will turn begrudgingly. After 20-30 mins, everything is good again and off you go, although pretty much back from where you came from to jack the thing up and have a look.

 

The fronts are configured to allow as much travel as possible, which is just the screw that you can turn.

 

The rears however seem to lack any adjustment at all and the replacement Moss cylinders doesn't have a slot in it to accept the shoe, which suprised me.

 

I'm clutching at straws now as this has been going on for some time. Is it possible to overbleed the brakes? Or is there an easy fix to my 5 mile summer journeys?

 

Many thanks

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Sounds like the master cylinder isn't returning fully. Have you got any slack on the push rod.

Do you have the restrictor fitted on the multi connector on the chassis just behind the divers side suspension. I if so you don't need it with drums. Remove the internals.

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If they are Girling does the slave cylinder slide freely in the backplate? If they are not free once the pedal is depressed and then released they do not return and release the shoes.

 

If it does not move easily the spring plates and locking tabs need to lie flat but are easily twisted and they need to be fitted with the correct orientation, and liberal copper grease along the edge of the backplate where the cylinder slides.

 

 

ps. I have also found that some slave cylinders have an external casting ridge left from production which needs filing off so the three clips and spring plates fit nicely.

 

 

 

Alan

Edited by barkerwilliams
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I had this occur a number of times on my disc-braked TR2 in the 1960s. I removed the innards of the restrictor valve 116197 and the problem disappeared.

Ian Cornish

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Also check the free play on the master cylinder/ pedal is correct.

 

My son's had this with their Sprite....they had no free play, heat and expansion caused the brakes to bind and sieze.

 

Iain

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+1 for checking fee play in the MC pushrod, the piston must fully return when foot off the pedal or else the fluid cannot get back up to the resovoir, & the brakes remain under pressure.

 

Bob.

Edited by Lebro
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I agree with Lebro. To confirm, when the brakes are binding crack open a union or bleed nipple and there should be a spurt of fluid and the brakes will return to normal. If this is the case then slacken the adjuster on the master cylinder.

Cheers Richard

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Adding to post #7 from Richard (Dic Doretti), releasing pressure at a bleed nipple can also suggest that the restrictor valve is the culprit (see my post #4), as this was what I had to do when I halted my TR2 with smoking discs!

Devs, you say that you fitted all new brake parts, but what about the restrictor valve? If one is present (it may not be, as drum-braked TR2s didn't have one), then after standing for 11 years, who knows how it will behave. It's unnecessary, so its innards can be removed and the casing put back - this avoids the necessity of getting a longer bundy tube.

Ian Cornish

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Thanks for the replies guys, much appreciated.

 

Just to confirm that everything is new from the master brake cylinder which is the only remaining part that I haven't replaced, so all the shoes, slaves cylinders, brake lines, 4 way connectors, T-piece connector etc. are all new. I don't have a restrictor valve on my set-up.

 

I do remember that the locking and spring plates on the slaves were a bugger to fit, so I'll double check those to ensure I have some free movement. As the Master cylinder is the only remaining part that isn't new, I'll also ensure it's returning the push rod as it's sitting idle for the 11 years I've been fiddling with the rest of the car.

 

Many thanks.

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Devs,

 

When fitting the spring plates they are fitted in opposite directions on each side of the car.

 

I find it easier to remove the handbrake cranked lever and fit the first plate nearest the backing plate, then slot the handbrake crank into place then fit the remaining two outer spring plates.

 

I hope you soon resolve your issues as the master cylinder and rear slaves are all pretty straightforward to check within a couple of minutes.

 

 

Alan

Edited by barkerwilliams
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As the Master cylinder is the only remaining part that isn't new, I'll also ensure it's returning the push rod as it's sitting idle for the 11 years I've been fiddling with the rest of the car.

 

Many thanks.

 

Prime suspect at this point, I'd say.

Can you get all four off the ground and apply the brakes, then release. (Drive enough to see symptoms first, if necessary) Do they all release immediately? All drag or just the rear.? If dragging do they release if you crack the master line. If yes it's most likely the MC. If just one end or they do not release when cracking the line, look there at the wheels.

Tom

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Pump up the brakes on the pedal, you may find the brake light stays on, remove the top from the m/c by means of the 4 screws, get a very fine needle and poke around at the bottom of the brake side of the m/c till you find the tiny pressure relief hole push the needle down it and if you get a spurt of fluid shoot up then thats the answer the rubber is obstructing the fluid getting back into the cylinder leaving a pressurised system, swollen rubber, oversized repro rubber, or crap not allowing piston far enough back, hope this helps.

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Please could someone ID this master cylinder set up for me? It's been changed from my original Lockheed hardware, however I can't get an exact match from my Moss catalogue. Please ignore the blue plastic connectors!

 

As always, many thanks!

 

 

 

TR2%20Brake1.jpg

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Well you wont find that in the catalogue! Thats a home made alternative Im afraid and I have no idea what from.

Stuart.

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