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TR2/3/3A Residual brake pressure valve - how much front wheel drag?

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AHS

AHS

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I just took the TR3A out - it ran & stopped great. While pushing it back into place, I noticed it stopped quickly when I stopped pushing, and upon investigation when I got the front wheels off the ground there is an even amount of drag on each side. I can turn them by hand with a few pounds force, but they won't spin at all. I've also noticed a lot of brake dust on the front wheels in the past. It gets very few miles.

The car is a very early TR3A with the original style Girling patent calipers and residual pressure valve. When I restored the car several years ago, I took apart the valve, expecting crud, but it actually looked perfectly clean & functional inside so I just reassembled it and installed it.

So my question is, what do others experience? Or is it wise to remove the valve?

Thanks, Andy
 
AHS said:
I just took the TR3A out - it ran & stopped great. While pushing it back into place, I noticed it stopped quickly when I stopped pushing, and upon investigation when I got the front wheels off the ground there is an even amount of drag on each side. I can turn them by hand with a few pounds force, but they won't spin at all. I've also noticed a lot of brake dust on the front wheels in the past. It gets very few miles.

The car is a very early TR3A with the original style Girling patent calipers and residual pressure valve. When I restored the car several years ago, I took apart the valve, expecting crud, but it actually looked perfectly clean & functional inside so I just reassembled it and installed it.

So my question is, what do others experience? Or is it wise to remove the valve?

Thanks, An
Hey Andy ,I cant say whats correct but I have the same setup and slight drag.Its noticeable if you stop on a very slight incline and you expect the car to roll back a little but doesn't,or if you park in the garage and try to roll the car forward and it drags a little,but still rolls.I get some dust,but the pads seem to be the same thickness they wre 9k ago,but then I don't use the brakes much.
I have thought about gutting the valve but everything is together so maybe next time I have to get in there.
Have Fun
Tom
Click to expand...
 
Ah yes, the 'hill-holding' feature.

What you are getting sounds about right and mostly harmless though it does seem to create more brake dust.

I have tried with both the valve intact and gutted and both seem satisfactory once you adjust your behavior and expectations.

With the valve working I occasionally let off the brake just before coming to a complete stop (say at a stop light) to confirm that the drag is easily overcome by just a little momentum.

With the valve gutted I know I will have to pump the pedal once to get decent binders after I have been driving a twisty road.
 
The valve is there because flexing of the stock axle and rotor assembly push the pads back and require more travel on the first brake application. A lot on the forum gut the valve, but then a lot use upgraded axles too, which should reduce the flexing and also keep the pedal high.

It's funny you mention the dragging. I drove the stock TR3 for 5 years and became accustomed to the car staying put on slight inclines while waiting for stop lights. When I switched to the TR2's 4 wheel drums, that was the only difference I noticed. The drums stop identically in normal driving, but you find the car rolls very easily compared to the stock disc brakes. It's to the point I would even wonder if the valve costs an MPG or 2?!?
 
Thanks gentlemen. It is good to know that the amount of drag I have is not a problem. To be sure I am safe, I removed both front wheels and inspected the pads, which are still good. Since this was hours later, the wheels spun easily. I will try your suggestions to see if I can detect the drag while driving. I might try gutting the valve next time I do brake work, because it just seems excessive in my experience, and must be making the rotors constantly hot.
 
Mine is gutted. I don't see the advantage of adding any resistance, but I live in Houston where actual hills are not common. I like that I can let of the brake while waiting for a traffic light, and the car will roll off the 'hill' (artificially elevated section due the thickness of the white painted line). I don't run uprated axles and have noticed the unusual amount of first time travel of the brake pedal after extended highway driving (or spirited driving on the track). The additional travel can be a little surprising, but I don't think having the guts in there would help much.

I have to agree it works best the way the you are used to.
 
My pre-60k TR3 came with the valve, my later TR3 never had one, so I guess one could assume that the valve is not necessary. The early car failed my State safety inspection this years because of the dragging front brakes, so I gutted the valve. Still a bit of drag so I removed the pads, that were quite tight, and cleaned the burs on the edges. No drag now and finally got the safety sticker.
I hardly notice a difference in driving.
Tom
 
Triumph must have decided that the valve was not necessary as it was not used on later cars (TR6 and maybe TR4s).
Berry
 
I have a 1960 TR3a. The first pump of the brakes is always much lower than the second pump regardless of how long or how aggressive I have been driving the car. I have always worried about this. No amount of bleeding has been able to change this characteristic.
As far as I know, my car has original axles.

Is the valve mentioned in these posts the restrictor valve on top of the 5-way connector?
Is my car’s braking condition because the valve has been gutted or because it has not been gutted?
What are the advantages/disadvantages of “gutting” this valve?
What is the process of “gutting” the valve?

Thanks.
Ron
 
Here's a couple of answers and opinions. Gutting mine, i.e. taking the spring and seals out, did not result in the necessity for a pump up before braking, even though that was the theory behind the valve. The flexing spindle was thought to cause the pistons to move away away from the rotor hence a low pedal. Warped rotors or loose bearings will do the same thing and poorly adjusted rear brakes will give the same sympton. Yes, the valve is on the connector. My experience is that there is virtually no difference in braking with or without the valve.
Tom
 
RonR said:
...What is the process of “gutting” the valve?
Click to expand...

Once you have it off it will be fairly obvious. Here is how the bits go together:

kuyc1Ff.jpg


Removing the guts just means undoing the end and taking out the spring and check valve, then threading the end back on.
 
The valve works. It definitely raises the pedal on the first pump. If you have upgraded axles, then you probably won't notice as much difference. The only down side to the valve is a bit of drag....but I actually liked it, as it saved holding the pedal at many lights.
 
From whart I think John is saying, since I have to pump the brakes on my TR3a one time to raise the pedal, the restrictor valve must have already been gutted. Is this correct?
 
Either that, or air in the system - might just need more bleeding, which of course you may have already done.
I have the brake drag also, and really dislike the feel of it, and don't want to decrease the car's mileage even a little bit - so the next chance I get the valve will be gutted on my '61 TR3A.
 
groupdeville said:
Either that, or air in the system - might just need more bleeding, which of course you may have already done.
I have the brake drag also, and really dislike the feel of it, and don't want to decrease the car's mileage even a little bit - so the next chance I get the valve will be gutted on my '61 TR3A.
Click to expand...

I don't think there would be any significant mileage difference,but I think it takes a little more clutch when starting out so clutch wear is probably slightly increased.
Tom
 
RonR said:
...I have to pump the brakes on my TR3a one time to raise the pedal, the restrictor valve must have already been gutted. Is this correct?
Click to expand...

I would also lean towards some air in the system. A clue might be the need for the extra pump right after driving a twisty bit of road - but no pump required if the brakes have been used followed by straight road, then used again.
 
Hi Geo.

The brakes always need pumped one time, regardless of the driving "style." They have been bleed the traditional 2-person way, and with a power bleeder, with no change in the pedal.

If putting the “guts” back into the restrictor valve will eliminate this condition, then I will be looking for the parts or for a replacement valve.
I would rather have the drag than having to pump the brakes every single time, which is how it is now.

Ron
 
Chuck, I will recheck the rear brake adjustment.

I rebuilt the entire brake system in 2011 when I returned the car to a driveable condition. In 2016, with the assistance of a friend who restores British cars, the front suspension was rebuilt and the brakes were rebleed and adjusted. We still could not get the brake pedal to be "high" on the first pump.
 
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