Page last updated 11 June, 2007
Technical Questions - Braking
9th June 2007
Do you know what the rear brake hoses for the 2500M are from? They seem to be at least 16 inches long.
sure TVR made these themselves - I bought a pair of rear hoses a few years
ago from unipart here in the UK - they did match some but from a list
of sizes rather than from a specific car - I do know TR6 ones were too
short. I have seen some for sale on ebay though (as for most things!)
- links are here:
22nd August 2006
By James Collier
|I've had the brake system apart and when I've come to bleed the system through again the "BRAKE " warning light on the dash is always on. The peddle has some feel but is low.
brake warning light is controlled by the brake pressure differential warning
actuator - see my Technical Manual in the brakes section for all the info.
Sounds like you have a leak somewhere as the pedal is low.
6th February 2006
By Wim Boon
I keep my foot on the brake pedal of my 3000M (1977), for example when
I am waiting for a traffic light, the pedal goes down very slowly. So I have
to let it come up after a few seconds and press it down again. There is no
leakage of oil or any other noticable failure.
I don't think this is the right way to perform for a braking system, so if
you can, please help me to solve this problem
sounds like you may have a servo problem, or air in the hydraulic system
of the brakes.
For Servo diagnosis: With the engine off, try pumping the brake pedal until you feel a solid pedal. Then with your foot pressed on the pedal, start the engine. If the brake pedal drops, the Servo should be ok, if it doesn't, there is a servo fault. Also check around the servo unit for signs of leakage. However this is sometimes hidden - the only way to see is if the fluid level in the reservoir has gone down a little.
For brake system diagnosis - you would normally see a leak, unless perhaps air is being drawn into the system. A leaking rear wheel brake cylinder can cause a pedal that loses pressure - it would be worth removing the brake drums and having a look.
29th December 2005
By Alan Nicholls
(The Brake Pressure Differential Warning Actuator) PDWA for the late model 3000m - I have found on the Web at www.astonmartin.com a parts promotion where they are selling the unit [with switch!] not for the list price of £143.68 but for £18.92+ VAT and postage = £24.58!
Lagonda December 2005 - part number 33 - 11489
|Many thanks - a bargain for anyone who needs one of these valves! Looks pretty likely the valve is the same.
18th June 2005
By Brad Barclay
I Have a 1970 TVR Vixen 1600. How do you replace the rear wheel studs? Are they from a TR6, or some other car?
up 21st June:
|I'm not 100% sure what the hubs are off. All I know is that normally studs are splined and are pressed out (or knocked out) using a suitably sized punch/press tool and tubular spacer behind the stud.
16th June 2005
By John Musacchio
I recently purchased a brake servo rebuild kit for my TR6, however I can't seem to find instructions anywhere, and I can't quite figure out how to take the servo apart. Can you either send me directions, or point me in the right direction? Thanks.
up 17th June 2005:
Follow up June 21st 2005:
Thanks a bunch Mark, I'll give it a try. I appreciate your assistance on this.
I have yet
to complete the master cylinder part of the technical manual, but in short:
Follow up June 20th 2005:
I'm not sure
what is in your Servo repair kit, but there should be an air filter for
the end under the rubber gaiter which is meant to be changed every major
What do people do to uprate them sensibly?
I have been told twin pots off a toyota pick up fit is this true? If so which pick up?
Four pot calipers are the most common way to do that....Wilwood make a set that fits and I'm told they're very good. The standard ones as you know are only just about adequate for lower speed driving. Toyota pick up calipers do fit but only early ones - I had some emails from someone in the USA who has done it successfully using ones from a 1979-83 Toyota 4wd Petrol pick up truck. In the USA they cost only $43.00 each re-conditioned. I tried to see the website but it has been removed. However here is an interesting forum chat that I came across which should help you a great deal -
11th August 2004
Do you know what sort or brake fluid should I use for a 1976 3000M please?
The manual is not much help in this area.
DOT 4 fluid
is fine...most cars use this so it's probably the only one
I do know
some people use Silicone Fluid but this cannot be mixed with DOT 4, and
it's DOT 5 classification.
by Steve Bourne
interior photo I see of cars of the same age shows the handbrake lever mounted
on top of the transmission tunnel whereas mine
is mounted on the side of the transmission tunnel. Is there any specific reason for this?
|I'm almost certain this was done because the overdrive gearbox prevented the top mounting being used - they had to come up with an alternative.