411 brake problems

[peter dowdle]

I am having trouble with my brakes. I have reconditioned the calipers and checked or replaced the flexible lines. Every so often the brakes lock on and wont release . The only way I can get the car to move is to release the pressure in the lines by loosening the brake lines at the master cylinder. I suspect this will be a Master Cylinder problem.

Question 1 has any one experienced the same thing.

Question 2 Does any one know the availability of a replacement cylinder ( I believe Mk 1 & Mk 2 are different to later cars)

I also need inner and outer tie rod ends

Regards Peter Dowdle

[peterf]

Hi Peter,
I am not at all familiar with a 411 master cylinder or any variations of it, however I have experienced the problem you described on two separate instances. ( not in a Bristol)

The first situation required overhauling the master cylinder, I suspected that the bleed valve in the cylinder was not operating correctly. It worked fine afterwards.

The second situation was the activating rod between the pedal and the master cylinder piston had a /lengthening/shortening adjustment by way of a threaded section into a coupling connecting to the pedal. This provided an amount of free play between the piston and the pedal ( much like the need for valve/tappet clearance) - but in this case not much, maybe 1/4 inch, just enough for the piston to return freely into its neutral position and not be restricted thus allowing the brake fluid to return without a resisting pressure, which if pressure was there would build up and eventually lock the brakes, as if you had your foot on the pedal.

The second situation was also very quickly fixed by way of loosening the bolts holding the master cylinder to the firewall because the adjusting coupling was very difficult to get to, at night in the middle of no-where.

Hope the above is of some help even though it was not in a Bristol but in a Chrysler/Mitsubishi.

Cheers
Pete
Ps. What type of accommodation do you want at Mildura :-)

[johnelfixit]

Peter,
Rare for servo's to fail, but having said that I recently had to replace one on a Skoda (VAG group). The symptoms were that the front brakes would stick on after repeated applications of the brake pedal and would only release after leaving it for some time or, like you, letting the pressure out from the hydraulic line.
Has the 411 got two servo's like my 412, or just a single?
One problem which can occur is that the vacuum chamber can fill with water or petrol over time (condensation). You can sometimes correct this by draining the chamber (means taking it off), but if it has got petrol in it this may have rotted the seals.
Repair kits for some servo's are available, see for example NORTHWEST AUTOMOTIVE HYDRAULIC COMPONENTS

This site has copies of catalogues which you can download.


Good luck

John P

[peter dowdle]

Thanks guys I forgot to mention I have 2 new boosters and I have checked freeplay on the rod.

most likely to be the bleedback on the master cylinder

Series 1 & 2 have a single cylinder but dual system .Bristol years ago used to carry stock of repair kits but are nearly 50 years old and don't last. Series 3 4 & 5 have a different cylinder as best I can gather and im sure could be adapted. Does any one know what other cars either of the cylinders are common too.

Any clue on tie rod ends

[Geoff Kingston]

The series 3 uses the same master cylinder as the Range Rover of that period and I think the same unit was used on the series 4 and 5, 412 and 603.
Geoff.

[peter dowdle]

thanks for that Geoff

[PEU186F]

The tie rod ends are relatively easily sourced once you know that they were also used on the Austin Healy 3000. But you'll need to work out whether you need LH or RH threads

[PEU186F]

Re my earlier post. Now I'm confused, I know what I told you re Healy track rod ends is correct for a 410, but I now note that Amsteer - see. You are being redirected...
list a separate rod end for the 411, for quite a lot more money.

They probably know best

[MYTA21]

Check any breather on the master cylinder. On the 409, the brake fluid level cap was replaced by plain pug- no breather. When brakes got warm, fluid expanded and calipers came on. just a thought

[johnelfixit]

Amsteer will make you track rod ends to pattern. They made me a couple for my 412 some years ago. Very helpful Company (then).
John P

[Kevin H]

Originally Posted by peter dowdle

Thanks guys I forgot to mention I have 2 new boosters ....

Peter, where did you get the boosters from and what type are they? Mine need replacing or rebuilding.

[peter dowdle]

Kevin i sent my originals to HYDROBOOST. He checked them out and said they would be expensive to repair, parts hard to get. He supplied 2 VH 40 AL boosters and filter covers. He comes with my high recommendation. Hes based at Echuca and specializes in power boosters for old cars 0354800886.

[Kevin H]

Originally Posted by peter dowdle

Kevin i sent my originals to HYDROBOOST....

Thanks Peter. Last time I spoke to the guy at Hydroboost he was too busy and referred me to a mob in SA. That was perhaps a year ago and I never got around to doing anything about it. However the approx price he quoted seemed quite high so I was thinking simply replacing them with a modern unit might be a better option. But if I'm going to buy new ones I would rather source them locally in Melbourne.

What do you think of the ones you bought? Did you have to change the fittings on your brake pipes?

[peter dowdle]

Finally sorted out most of my steering and tie rod end problems. My two left hand tie rod ends were worn and from the forum i discovered the company AM STEER.
They list left and right hand ends. I subsequently ordered a left and right hand threaded ends without first checking ( assumed I needed one of each). It turns out that on both ends of the outer rods the threads are left handed. Quite why this would be I cant guess. The question begs why would AM STEER make a right hand threaded end for a 411 when there are none on the car. The middle rod has a left and right handed ends but these are larger than the outer ends .Mine dont need replacing at this stage but does anyone have any idea what they maybe off?

The lead that Austin Healy 3000 rods fit the outer arms is infact correct . These are the ones from the center rod on the Healy but in Australia they come in pairs left and right only.

To adjust the toe in on the 411 you change the length of the center rod . What then is the purpose of the adjustable outer rods ?

I also discovered that the steering idler also acts as a steering damper. I filled it with oil and it now acts like a steering shocker.

[PEU186F]

Some confusion here, I think.

"Both ends of the outer rod are left handed". So when you slacken the lock nuts and rotate the outer tie bar whilst the rod ends are mounted on the car one end screws in at the same rate as the other end screws out, so no adjustment occurs.

You ask why Amsteer should make a right hand threaded outer rod end (for a 411 when there are none on the car). They do but not for a 411. The 407, 408, 409 and 410 all use 5 right hand threaded ends and 1 left hand. The Austin Healy also needs a RH threaded end, which is probably why they are sold in pairs in Australia. I don't know why Bristols changed from predominately RH to LH.

The rod ends on the middle rod on the 407 to 410 cars are the same size as the outers. One wonders why Bristols changed to bigger ends on the middle rod on the 411 but your confirmation that they did explains why the Amsteer website lists a larger and more expensive rod end for Bristol on their website. It also explains my confusion earlier in this correspondence. I don't know what car or light truck shared these but you can get them from Amsteer.

Other readers may like to note that the outer rod ends (and the inners on the 407 to 410) are as used on the Healy 3000, not the earlier Healy

[peter dowdle]

PEU186F ( WHOEVER YOU MAY BE)

Yes you are right one end turns in the other out meaning no adjustment. Why then is there any need for left handed threads , why not have fixed lenght rods like the austin healy?

The AMSTEER only lists two ends for 411s no mention of other models .I have 2 amsteer ends and 2 austin healy ends and they are almost identical. They do not list the larger ends for the middle rod. My guess is the Austin ends are ex Moss Motors.

[peter dowdle]

Still trying to sort out locking brakes . I need a lead on what other vehicle might have had the same master cylinder as shown in photo. It seems to be only used on series 2 411s. I need a repair kit as the cylinder itself is in very good condition.

Regards Peter Dowdle

[Kevin H]

Hi Peter,
It's odd that the 411 S2 would have a different master cylinder to the other 411 series, although granted it is not impossible, because Bristol did try other brands of components from time to time

Do you know this for sure?

Is it possible someone has fitted a different one to your car at some stage?

[peter dowdle]

Kevin I have researched this closely.If you check photos of various cars you will find series 3 4 & 5 all have a plastic tank , These are common to 70s80s range rover and are held in place with 2 studs on the firewall. What has surprised me is that series 1 have the same mounting system although a completely different cylinder. As you can see from the photo mine doesn't mount that way rather it has 2 cross bolts which attach to two parallel fabricated little walls .These are clearly original on my car. A search of the internet found a site CLASSIC PARTS on ebay. They list my cylinder as suitable for 411 1969 to from memory 1977.Listed at 365 pounds.

My brother Geoff had a series 1 which has chambers of different sizes. He purchased a kit from Bristol Cars but being very old stock it failed. With some modification he eventually fitted an xj6 mk 1 cylinder.

Clearly then there are at least 3 variations that i know of.

Im hoping to find a brake specialist in Melbourne who carries a large range of separate rubbers. Any clues ?

[Kevin H]

Originally Posted by peter dowdle

Im hoping to find a brake specialist in Melbourne who carries a large range of separate rubbers. Any clues ?

I don't know anyone Peter, but I know people who will know. I will ask around.