Brake restrictor valve

[Norman D]

My TR3a which I am building from a pile of bits I bought has a restrictor valve in the hydraulic line, I can not determine where this fits except that it screws into the five way junction,pointing vertically according to the Moss catalogue. My problem is that it seems to be between the master cylinder and this junction union meaning that it will restrict pressure to all brakes front and rear, is this correct, sounds dangerous to me, most (relatively modern ) cars have a restrictor in the rear brake line onlyto stop rear brakes locking. Do I need this item anyway as it is not listed for all model variants. Thanks in anticipation. There is a picture of it in Haynes manual but no mention in text, the factory manual I have does not mention it at all.

[ianc]

It is not a restrictor, it is a spring-loaded valve. its purpose is to maintain a small pressure in the system so that knock-back of the disc pads (when cornering energetically) is minimised. Not worth the bother, in my opinion. If you don't want to make a new (longer) bundy tube to span the gap left by removal of the valve, just dismantle the valve, remove its innards and re-assemble it (remember to use the copper washer between the two halves).

Ian Cornish

[pfenlon]

Ians on the money

 

Junk it, nama problema Honestly.

[Richardtr3a]

I have a receipt from the local Standard Tiumph agent in Brighton, for the removal of the restrict or which was causing my brakes to bind up. Ir was a mistake by ST at the time. I have been running ever since without one.

Good luck, Richard

[Norman D]

Thanks everyone for your advice and info. I shall remove this device and add simplicity. It must make it impossible to press the pistons back when renewing brake pads without undoing bleed screws, which is current practice with antilock brakes-- Triumph ahead of the pack! May put valve on ebay in case anyone really wants one.

[Trevor S]

I bow to those with greater knowledge but must admit that I have stuck with the valve on both my TR4 which I've owned for 14 years, and my current TR2 rebuild with Girling braking system. Triumph always seemed to be strapped for cash and I find it difficult to believe they would fit a part that they could have got away without fitting. Views differ but I'm with Viv on this one and I'm keeping the valve. Maybe I'm a little too anxious when it comes to brakes.

Good luck with the rebuild Norman, do let us know how you get on.

Edited April 8, 2009 by Trevor S

[Don Elliott]

Trevor - Like you I still have the restrictor valve on my 1958 TR3A. It's the same one that came with the TR when I bought it new 51 years ago. I've had it apart at least twice and never had an issue with the brakes or with its operation. Here is a sketch of it that I drew during my restoration from 1987 to 1990. Maybe those who "think" it's causing a problem, have it re-assembled incorrectly. It's also shown in the Haynes Manual.

[greasemonkey]

Trevor - Like you I still have the restrictor valve on my 1958 TR3A. It's the same one that came with the TR when I bought it new 51 years ago. I've had it apart at least twice and never had an issue with the brakes or with its operation. Here is a sketch of it that I drew during my restoration from 1987 to 1990. Maybe those who "think" it's causing a problem, have it re-assembled incorrectly. It's also shown in the Haynes Manual.

 

Yes, mine has it too & it's been no problem for 35 yrs. It does puzzle the MoT man though as he can't turn the front wheels without a lot of effort - but I remind him each year!!

[Don Elliott]

I don't have any problems rotating my front wheels when the front end is up on jack stands. If your wheels are dragging, are your front wheel bearings too tight ? Are the pistons in your front calipers rusty or tending to wedge or is dirt causing them to stick ? I've been using silicone brake fluid in my TR3A for the past 19 years (100,000 miles) and I think the lubricating properties of this fluid permit very smooth operation so the pistons in the front calipers move back nicely. I never have a "soft" pedal during braking because the pads and pistons move back just off the rotor. My pistons are the original ones (51 years) from new in 1958 with over 180,000 miles total on them and I put in new seals for the pistons and calipers in 1990.

[greasemonkey]

I don't have any problems rotating my front wheels when the front end is up on jack stands. If your wheels are dragging, are your front wheel bearings too tight ? Are the pistons in your front calipers rusty or tending to wedge or is dirt causing them to stick ? I've been using silicone brake fluid in my TR3A for the past 19 years (100,000 miles) and I think the lubricating properties of this fluid permit very smooth operation so the pistons in the front calipers move back nicely. I never have a "soft" pedal during braking because the pads and pistons move back just off the rotor. My pistons are the original ones (51 years) from new in 1958 with over 180,000 miles total on them and I put in new seals for the pistons and calipers in 1990.

 

Don, the front wheels only drag for one or two turns & then free off. I've always put this down to the restrictor valve which seems sort of logical. I rebuilt my 3A in 1976-84 and used silicone fluid then with all new (stainless steel) pistons, pipes, seals etc etc. Ran with no problems at all - including a 6 year lay-up at one stage - but felt guilty about still using the same fluid in about 2001 so I changed it & all the seals - just for fun. BUT, I've found the lubricity of silicone fluid lacking, to such an extent that it was impossible to get the caliper seals in using it as a lubricant - I struggled for hours, then tried a bit of Girling red grease and they popped in in 30 seconds!! Also, the clutch pedal sometimes goes floppy, I guess the piston isn't fully returning in the slave cylinder, again because of the low lubricity. No problem with clutch action and it isn't holding pressure on the clutch release so I've lived with it for 25 years!!