22 replies to this topic

[Staddon]

Mini failed on this area the other day, any one got any ideas where i can source one? 

 

The mini is a '89 city e, 998cc engine. 

 

Thanks in advance! 

[Staddon]

Or if anyone knows other names for the part required, or where the part is located in an 89 city e mini, that'd also be useful 

Edited by Staddon, 21 July 2015 - 09:11 PM.

[cal844]

Mini doesnt have one, just a pressure valve on the bulkhead

[Spider]

Is this the one in the engine bay, on the front rail of the rear subframe (unlikely) or the side rail of the rear subframe?

 

Cal844, some Minis did have them.

Edited by Moke Spider, 21 July 2015 - 09:10 PM.

[Staddon]

Thats what MoT place listed it as, however, i think its this part that needs to be replaced. http://www.minispare...c/FAM7821.aspx#

 

 

Not certain though 

[Staddon]

mini spares states that this valve was relocated from ear subframe to bulkhead from 88 onwards when servo was fitted 

Edited by Staddon, 21 July 2015 - 09:22 PM.

[Cooperman]

The one on the bulkhead is the one with the M10 Fine metric threads, whilst the threads on the other end of the pipes are 3/8" UNF. Be careful if the pipes are renewed. Very bad design for a safety-critical system.

[nicklouse]

The mini does not have a load sensing valve.

But it has had a number of pressure regulators/limiters.


A load sensor needs to have an attachment to the suspension to see how much it has been compressed to adjust the braking pressure allowed. Which is why modern cars that have been lowered have to have it adjusted to stop the rear brakes locking up.

All the Valve on the Mini does is limit the max pressure that can be applied.


But back to the OP dual circuit then that might be the issue. BUT I would be asking the testing station if they could provide more info as to the fault or persived fault.

[Spider]

Oh, sure?

 

What about these then?

 

http://www.7ent.com/...80-13h7757.html

 

(although that says to 1980, we had them on our local cars up to 83 when production ceased and they were fitted well after that)

 

<edit: Mini spare also list them, but they say to 74  http://minispares.co...ck to catalogue

 

none the less, they are a load sensing true proportion valve, that take in to account load, speed and braking G's. I usually run these on most of our cars >

Edited by Moke Spider, 21 July 2015 - 09:59 PM.

[nicklouse]

Here we have what I was expecting. And hoping for.

The word load.

What is load?

Add more load to a car you need more braking power the Mini does not do this.

The ones you linked to are just inertia valves that shut the flow to the rear due to the rate of retardation nothing to do with load. But as the rear tyres are being "un loaded" with the weight transfer which also activates the inertia valve.

The inertia valve not working should not show up on a UK MOT as the car is not put through conditions that would activate it.

But again I would be wanting to know how the car failed the MOT as that would show what route to take for fixing it.

But then I can't remember which setup an 89 mini had any way.

[Spider]

Add more load to a car you need more braking power the Mini does not do this.

 

 

Sorry Nick, but I do beg to differ here. They don't increase any braking power to the front brakes, but they do increase braking effort done by the rears. As Load is increased, ie more weight) in to the rear or even in the middle of the vehicle, it's attitude levels out and as these have a ball that runs up a ramp to operate them, that ramp angle also increases, so allowing a higher fluid pressure to the rears, The angle that these are mounted at is also fairly critical, to maintain balance between front and rears.

 

Likewise on faster stops, the rear will lift more, thus reducing rear braking, in proportion to the stop and the load.

 

They work, they work just as this and they work well.

[Spider]

Here's one I set up in one of my Minis as an adjustable type (not the best angle)

 

 

And I think ? Vizard also mentioned much the same in his early Mini book.

[Minidarren83]

This I rediculous you would need the rear wheels to be a foot off the ground before the ball bearing would travel uphill in the tract to reduce rear braking effort caused by loading or unloading your car. It is an inertia valve that is operated by the deceleration of the car sending the ball up the tract as the car rapidly slows down thus reducing the braking effort to the rear wheels to stop the car spinning

The reason the angle is important is this type of valve is to eradicate false operation under light braking and changes in the vehicles ride hight due to weight being added or removed ie passengers

A load sensing valve is a constantly variable valve operated by the vehicles suspension and is connected via a linkage to a trailing arm and is mounted to a fixed point on the vehicle

David vizzard was not worried about how he was going to stop with his fat mates in the back but he was worried about hard baking in corners leading to rear wheel lock and inevitable about facing

[nicklouse]

Add more load to a car you need more braking power the Mini does not do this.

 
Sorry Nick, but I do beg to differ here. They don't increase any braking power to the front brakes, but they do increase braking effort done by the rears. As Load is increased, ie more weight) in to the rear or even in the middle of the vehicle, it's attitude levels out and as these have a ball that runs up a ramp to operate them, that ramp angle also increases, so allowing a higher fluid pressure to the rears, The angle that these are mounted at is also fairly critical, to maintain balance between front and rears.
 
Likewise on faster stops, the rear will lift more, thus reducing rear braking, in proportion to the stop and the load.
 
They work, they work just as this and they work well.

You miss my meaning. I was talking about brake load sensors (not mini pressure regulators or inertia valves) brake load sensors can and do allow more braking force to be applied to the rear brakes if the suspension is compressed buy there being a greater load in the rear of the car/van.

What I am pulling up the MOT station about is they have failed the car on something it does not have.

Like I said I would like to know that was measured to show the result that gave the fail. On the minis with the bias valve it just shuts of the fluid to one circuit so you can still stop (or spin) on the other circuit.


Back to the inertia switch yes it does allow more power to the front without increasing the force at the rear, just by shutting of the glow to the rear. Until the fluid force is greater than the inertia valve or the rate of retardation is reduced alowing the valve to open again.

I think we are actually agreeing on how things are on the mini.

My bee is the wording on the MOT fail sheet.

[ChopperHarris]

Yep Minis have never had "load" sensors, not even the commercials.
Its just a terminology thing chaps.
I wish I had known about what you are referring to Moke, when I built my Stimson Trek, which I could lift the back up with one hand!
And wheely in reverse