Mot advise, brakes.

[ianlea73]

I've added diagrams of current set up & proposed set up.
The 4 way splitter is available on ebay from a range rover I believe.

The rear brake compensator on my hijet pick up is seized solid & a replacement is over £300.
As I intend on never having load in the back as I'm going to fit a timber liner & metal stripes can I just remove it, replum the brake pipes, cut off any brackets so it looked like it was never fitted?

Is it a necessity?

[Rich]

Without it it’ll be potentially horrible to drive as it’ll lock the brakes on the rear car too easily. It’s there to proportion brake force Vs. Load. You would be better off fitting a manual valve in its place, tuning it to suit the bed you intend to build and then leaving it alone.

[ianlea73]

Apr 23, 2023 21:29:49 GMT Rich said:

Without it it’ll be potentially horrible to drive as it’ll lock the brakes on the rear car too easily. It’s there to proportion brake force Vs. Load. You would be better off fitting a manual valve in its place, tuning it to suit the bed you intend to build and then leaving it alone.

A manual brake bias valve?
I'll have a look on ebay.
Cheers.

[minijohn]

Classic Minis had valves to reduce the pressure to the rear brakes.
Should work perfectly on your Hijet.
£73 incl VAT

www.minispares.com/product/Classic/21A1774.aspx

[Rich]

Apr 23, 2023 21:54:35 GMT ianlea73 said:

Apr 23, 2023 21:29:49 GMT Rich said:

Without it it’ll be potentially horrible to drive as it’ll lock the brakes on the rear car too easily. It’s there to proportion brake force Vs. Load. You would be better off fitting a manual valve in its place, tuning it to suit the bed you intend to build and then leaving it alone.

A manual brake bias valve?
I'll have a look on ebay.
Cheers.

That’s the one. You can fine tune it to make sure the brakes perform correctly and safely with the (lack of) weight on the back end without the MOT drama that way. 👍🏻

[stealthstylz]

A manual proportioning valve is the thing to try, but you need to be careful as often they don't reduce as much line pressure as OEM valves.

[MOGGY]

Or un-seize yours, I’ve done this many times for mot’s

[slackerTHEpinstriper]

For jobs like this, I cannot recommend this stuff enough

www.ebay.co.uk/itm/222799217914

[ianlea73]

Apr 23, 2023 22:18:17 GMT minijohn said:

Classic Minis had valves to reduce the pressure to the rear brakes.
Should work perfectly on your Hijet.
£73 incl VAT

www.minispares.com/product/Classic/21A1774.aspx

Is that adjustable manually or flow control?

[redratbike]

oh yes this is fun

my dad couldn’t get a decent pedal in an old mini van he gave me.

he pulled the compensator valve out which i didn’t know the consequences of and lo and behold the first time i jumped hard on the brakes whilst racing a 3.0s capri through the lanes in a proper david and goliath moment.

came into a tight bend stomped on the pedal and the car swapped ends we hit the bank backwards and went over the top and rolled in the field a number of times.

i can remember my mate Tony shrieking yee-hah in the finest dukes of hazard style as we flew though the air.

in the morning the mini van wasn’t there and i claimed it must of been stolen as didn’t want to admit i had crashed it 3 days after getting it on the road .


only found out years later what he had done and put 2 and 2 together

[minijohn]

No they're not adjustable (well not supposed to be) but I've heard of people dismantling them and changing the internal spring.

This diagram shows the fitting location (item no 20)

www.minispares.com/catalogues/classic/Classic~Mechanical~Parts~Manual/Brake~System/Single~Line~Brake~Pipes.aspx?1~9~78

Note there are a couple of different versions.
The Cooper S had disc brakes and a servo so I would assume had higher pressures in the brake lines.
A couple of "test" emergency stops in a car park would soon let you know if the pressure was wrong.

[ChasR]

Apr 24, 2023 6:43:40 GMT stealthstylz said:

A manual proportioning valve is the thing to try, but you need to be careful as often they don't reduce as much line pressure as OEM valves.

I’m guessing the the proportioning valves can work all of the time as well (Ie, the car going over compressions), which in theory a manual valve won’t be able to do unless he is changing it all of the time.

[ianlea73]

I've added current & proposed brake set up to my first post.

[Rich]

May 9, 2023 18:19:45 GMT ianlea73 said:

I've added current & proposed brake set up to my first post.

Do not combine both outputs from the MC into one amalgamated output. One line should operate one front brake, and one or both rears, and the other should operate the opposite rear and front. If you have one rear line then one run rear line from one of the MC outputs. If you have two rear lines which is what it looks like the photo of the chassis shows then you need to run opposite corners off each MC output for sensible safety. This may mean you need 2 brake bias valves but it also means you won't lose your entire brake hydraulics in the event of line failure.

[ianlea73]

May 9, 2023 18:54:26 GMT Rich said:

May 9, 2023 18:19:45 GMT ianlea73 said:

I've added current & proposed brake set up to my first post.

Do not combine both outputs from the MC into one amalgamated output. One line should operate one front brake, and one or both rears, and the other should operate the opposite rear and front. If you have one rear line then one run rear line from one of the MC outputs. If you have two rear lines which is what it looks like the photo of the chassis shows then you need to run opposite corners off each MC output for sensible safety. This may mean you need 2 brake bias valves but it also means you won't lose your entire brake hydraulics in the event of line failure.

Do you mean the 4 way splitter I proposed in my 2nd pic?
The 1st pic is factory 5 way splitter that shares front & rear ports too?

[Rich]

May 9, 2023 20:32:51 GMT ianlea73 said:

May 9, 2023 18:54:26 GMT Rich said:

Do not combine both outputs from the MC into one amalgamated output. One line should operate one front brake, and one or both rears, and the other should operate the opposite rear and front. If you have one rear line then one run rear line from one of the MC outputs. If you have two rear lines which is what it looks like the photo of the chassis shows then you need to run opposite corners off each MC output for sensible safety. This may mean you need 2 brake bias valves but it also means you won't lose your entire brake hydraulics in the event of line failure.

Do you mean the 4 way splitter I proposed in my 2nd pic?
The 1st pic is factory 5 way splitter that shares front & rear ports too?

I doubt it merges brake force as it’s basically converting a dual line down to single which no manufacturer would do. Build it as a diagonal split, and bask in the knowledge that if you ever have a line fail you’ll still have 50% brake force available to stop the truck.