• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR2/3/3A tr3 brake restrictor

Share this page

S

sp53

Yoda
Country flag
Offline
Hi all does anybody remember the post that was out there about the tr3 brake restrictor valve? I am trying to bleed the brakes on this restoration I have been working on and I cannot get any pedal and I cannot not get fluid to come out past the 3 way union that has the restrictor. If I remember right, it was said that I could just remove the guts out of this thing and go that route.
Steve
 
You can just remove the guts of the valve. Everything will continue to work fine. If it's really gunked up, or been assembled wrong this may fix your problem. If it doesn't, you have another problem -- though I don't know which one.
 
The valve was put in there to keep some residual pressure in the brakes because of axle flex which pushed the pistons back in the bores slightly. This was supposed to push the pistons back out and keep the pads in close contact with the rotors so the next time you stomped on the brakes, you wouldn't have excessive travel.

I gutted mine, and unless you drive really hard, you won't notice the difference.
 
I had a problem with front brake squeal. A LBC mechanic suggested removing the guts of the restrictor valve and once it was out the squeal was over. There is no effect on braking. Art's explanation of the purpose of the valve would seem to explain why it could cause squealing.

Gary
 
I had a problem with front brake squeal. A LBC mechanic suggested removing the guts of the restrictor valve and once it was out the squeal was over. There is no effect on braking. Art's explanation of the purpose of the valve would seem to explain why it could cause squealing.

Gary
 
Hmm, I posted this before, but it seems to've disappeared?

I doubt the RPV valve is the problem, though I agree it can be removed with little risk. If it was blocking the flow of fluid, you would get a high, hard pedal.

My guess would be that your MC is air-locked and needs to be bled right at the MC. Try stuffing a rag under it and loosening the outlet fitting, see if you can get some fluid there.

Removing the RPV can cause the pedal to be low after 'spirited' driving, but a quick pump will bring it back up. Or, a better solution IMO is to install the uprated front spindles & spacer offered by TRF (developed as I recall by the late "uncle jack" and manufactured by Alexander Racing Equipment).
 
In part the restrictor was early thinking on how to keep the pads close to the discs as they wore down. The theory was that the restrictor would always keep the brake pedal high, despite pad wear.

Some of the internal parts in the restrictor, such as the spring, are made of steel and rust over the years due to moisture in the brake fluid.

If you take the restrictor apart and clean the parts with a wire brush, then reassemble, it will work again as new. Obviously cleanliness is essential being a brake part, and wash the parts in spirits.

Always make a diagram if dismantling the restrictor, so it goes back together correctly. Don Elliott has posted an excellent drawing he made of the internals for re-assembly.

As said, there seems to be no great problem with ditching it, and in fact it was deleted by the factory during TR4 production.

Viv.
 
Here's mine. Haynes Manual also shows it.
 

Attachments

  • 20080.jpg
    20080.jpg
    52.6 KB · Views: 379
So Frank you reckon save the single malt for the brake part cleaning and swig down the metho ?

Sheesh, burb, hic....bad news....not trying that again !!!.

Ciao,

Viv.
 
The restrictor valve is one item that I never work on before and it kinda bothers me. Well I gutted out the restrictor valve and got the pedal to pump up, but not as good as I would have liked it to. There was rust and gunk in there and perhaps that did not permit the fluid to move past. The valve had been dry for probably 25 years. I hear you Randall, but in this case, I had brake fluid right up to the restrictor valve. I am using Dot 5 for the first time and perhaps I still have some air in there. Perhaps if I cannot get the pedal up, I will put the cuts back in and see if that helps, but then I would have to re-bleed. I like this dot 5 stuff because it seems so user friendly around the paint. I appreciate all the feedback and found comfort in the fact that they removed it on the tr4.
Steve
 
Steve,
I'm using dot5 too and I've found that even after a very painstaking bleeding it will seem a bit soft. I've also found that after a few drives they tend to firm up.
Dot5 will suspend air pretty well and from my experience it appears some of the air will find a way back to the resevoir when driven.
I think the movement, bumps etc assist in this.
 
What works for me is to always take a break after adding DOT 5 to the reservoir. If you wait an hour or two, any bubbles introduced during the pouring process should rise to the top and thus avoid being sucked into the MC.
 
Back
Top