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Leaking Brake Fluid -- What is This Part?

stuzbot

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I get what yous are saying. But, the new one cost £150. Plus I've spent about another £100 on brake pipe, flaring tool, pipe bender, nuts, etc. So it's going to come in at about £250 odd, just to replace a pissy wee valve that [as I said before] would probably never be called into action anyway, as I'm not going to be doing any towing with the truck.

Obviously, if the old one is properly seized, I'll fit the new one. But, if it just needs freeing up, then it seems a bit daft to throw it in the bin --especially since it's the original ASIN one, which clocks in at £200 new.

Anyway, as I said, I'm leaving it to soak in PlusGas again tonight, now that I've got the crud away from round the piston edges. So I'll see if that's done anything by tomorrow. If not, then bullets will be bitten and the new one put in.

EDIT:

I've just had a closer look at the piston area by the light of the silvery.... er... torch and I can see a gap, making it look like there's a circlip holding the piston in place. If so and if I can persuade that to come out, it looks like maybe the piston could be pulled out for inspection and cleaning.

20210812_212113.jpg
 
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stuzbot

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BTW: Whilst I was doing my 'thumb-twiddling waiting for brake tools to come' cleaning of parts today, I also gave the skanky old brackets a bit of spit and polish too...

20210812_135051.jpg


20210812_163309.jpg


Getting rid of all that crud must already have doubled the value and halved the axle weight of my truck.
 

Tractionman

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Good thinking Stuzbot, Aisin is the real deal. That valve/ piston is looking better close up, and although I can't see it in that shot, a retaining circlip makes sense.
The bracket, what a transformation. Looks like no metal has been lost to rust, and once painted no one will know any difference. Nice to hear you're still upbeat about a series of setbacks, in your first Land cruiser experience, and as you will be working with new pipes and good clean parts, here's hoping it's all good news from here mate.
 

stuzbot

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here's hoping it's all good news from here mate...

Thanks.

This was the bit I thought looked like the gap in a circlip. Of course, it could just be a bit of metal chipped off. But the edges look quite regular...

20210812_212113wee.jpg
 

Jake the Peg

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Bolt the old valve back up on the bracket and give the piston a tap with the hammer, it should retract into the housing. once you have the new metal brake pipes made you can use the fluid to pump the piston back out, then keep working it until its properly free.
you might also find it easier to get a good brake bleed at the calipers if you clamp both rear flexi pipes and bleed the LSV then one caliper at a time
 

Tractionman

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I see that now Stuz, and on your other shot now you have explained it. I'm hoping for you it IS some sort of retaining/circlip, although it doesn't look the regular type with eyes to get the circlip pliers on. Hopefully you can get it out (If that's it) and it will all come apart easily.
 
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stuzbot

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Well, it looks like the new LSV is going on, after all.

Old one was still seized solid this morning, after a second night's soaking in PlusGas. By dint of putting a socket on the piston and twatting it with a BFH™, I did manage to move the piston down by about a mm. Enough to confirm that there was indeed a circlip in there, presumably to allow the piston to be pulled out. But even wedging it in a vice and using a cheater bar and squeezing the feck out of it, it wouldn't move any further. So it must be a solid lump of rust inside.

Screenshot 2021-08-13 at 16.37.04.png


In other news, I've realised I forgot to mark which of the crusty broken off stumps of brake line goes to which port on the LSV. There are two lines that run forward along the chassis, to the front of the vehicle and one line which goes to the rubber pipe which connects to the brake lines on the rear axle. I know one of the lines coming out the side of the LSV goes to one of the chassis rail lines [because it didn't snap, so still has the plug on it and I remember which one it was]. And It seems logical that the port beside that on the LSV would be for the other brake line which runs along the chassis rail. And, by a process of elimination, the port on the top must be for the rear axle line.

Anyone can confirm or deny that, just in case it's not that logical?

Screenshot 2021-08-13 at 16.48.44 (2).png
 

Tractionman

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Cant help with the pipe positions mate, sorry it didnt work out with your plans.
 

stuzbot

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Cheers Bob. Sorry. Didn't realise you'd already posted that. Now I'm more confused than I was to start with. I was 99% sure that the two chassis rail pipes were the ones that came out together from the 'side' of the LSV. I wonder if mine had been taken apart before and plumbed back in wrong? Seems unlikely, given the amount of crud and corrosion on them.

Bit of a pisser really, because....

I went out in the drizzle this morning to try and get the old knackered pipes off. Got the two chassis rail ones off without too much difficulty, apart from working out how to persuade them over the top of the suspension housing. The other one, that goes to the rear axle and that I'd left til last, thinking it would be the easiest, proved to be more of a challenge.

I had a tentative twist at the nut on top of the axle that connects the brake line to the flexi-pipe and there was no way that was going to come off without a lot of pain & misery. It's almost impossible to get a spanner on, what with all the gubbins round axle and fuel tank in the way. And what shallow purchase I could get on it with a spanner, I could tell was just dying to slip and round it off.

As I lay there damply, waiting for the smoke to start billowing out my ears and the swearing to start, I was interrupted by the missus who came out to tell me Mr. Amazon had been and delivered my brake pipe flaring tool. Thus completing the set of all the things I needed to start making new pipes. So I jumped at the chance to play with a new toy and left the rear axle pipe for another time.

Up in the house again, I had a couple of practices with the flaring tool and then got stuck in. Based on my earlier assumptions that both chassis rail ones went to the two ports on the side of the LSV, I made up two new ones the same, based on the one that had come off intact...

20210814_143947.jpg


So Bob's really pissed on my chips now, by pointing out that one of these actually goes into the port on the top. I'll have to see if I can adapt one of them to fit.

Flushed with my new brake pipe making skills, I ventured outside again to have another crack at the rear axle line. This confirmed my earlier opinion that I really didn't want to have to face the misery of trying to get in at that fecker, if I rounded off the nut. So, instead, I cut away the plastic covering down at the broken off end where it goes into the LSV and found that it was actually corrosion free underneath. So I decided to chance trimming it back and putting a join section in there, rather than risk the inevitable torment of trying to remove the whole pipe.

20210814_161615.jpg


20210814_162536.jpg


Then I made a short section for the top of the LSV to bridge that gap [I was using the old LSV shell loosely bolted in place as a kind of template to judge pipe lengths & angles, etc]......

20210814_165445.jpg



Of course, this too was based on my assumption that the top port on the LSV was the one that went to the axle pipe and that notion now smells somewhat of fried potatoes and urine too. Dammit! --and there was me thinking I'd been really productive today. Up until rain stopped play.

Oh well. Back to the drawing board!
 

BobMurphy

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So Bob's really pissed on my chips now, by pointing out that one of these actually goes into the port on the top. I'll have to see if I can adapt one of them to fit.

OK, This is how I think it works - subject to the usual caveats, disclaimers, get-out clauses (i.e. I haven't cut one open):

Back to the picture:

DSCN5634 copy.jpg



Taking the two mounting bolts as the centre line, we have one pipe below and two above.

The lower one (lower pipe on chassis rail) is the feed from the brake pedal.

The upper one above it (to rear axle flexi-hose) is the output to the rear brake calipers.

Under normal conditions applying the brakes allows brake pressure to pass through the (open) valve and work the rear brake calipers.

So far so good.

Now, when things go pear-shaped and you are standing on the brake pedal with teeth clenched and eyes popping . . .

The rear of the truck lifts, the LSV operating lever drops and shuts the lower feed pipe off from the upper output pipe. You are left with a fixed amount of pressure in the rear brake system.

By now it is probably too late and the rear wheels are locked and skidding. The ABS Gremlins join the party and have to reduce the pressure at the rear brakes to stop the skid.

There is no point in reducing the pressure in the feed pipe as it is locked-off and no longer affecting the rear calipers - which have pressure.

The ABS System has to reduce the pressure on the caliper-side of the circuit, which it does via the third pipe which is above the centre line and therefore isolated from the brake pedal circuit.

Hence the pipe above the centre line marked "To upper pipe on inner chassis rail" which goes to the ABS Modulator.

I would imagine you don't get the 'pumping' feeling in the brake pedal as its not being affected by the ABS as the fluid pressure in the calipers is reduced.

Unless, of course, the front wheels are also locking-up !

This seems to be a logical explanation to me . . . Unless someone knows different :icon-wink: .

Bob.
 

stuzbot

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Can I borrow those 'caveats, disclaimers and get-out clauses' a minute?

I'm not disputing your 'what pipe goes where' diagram of the plumbing. But, that's not my understanding of the function of the LSV. Bearing in mind I had a similar LSV on a couple of 3,5 tonne VW vans I've had, which didn't have ABS.

On those, anyway, the LSV was obviously nothing to do with ABS [what with it not existing on those vans!]. What it did was semi-permanently alter the amount of hydraulic brake pressure going to the rear axle, depending on how much cargo the van was carrying:

Normally, with the van not heavily laden, the hydraulic pressure was as divided 60%/40% front and rear [you want most of your stopping force at the front end where there's most weight over the wheels]. However, when the van was fully laden, the rear springs compressed, decreasing the distance between axle and body and [in Land Cruiser terms] pushing the lever on the LSV upwards, which evened out the hydraulic pressure, so it was now balanced at 50%/50% front & rear.

I assumed the LSV in the Land Cruiser performed a similar function. For such times as when it was really loaded up in the back, or weighed down at the back by towing. As then you'd want more braking force over the rear wheels, as they might now be carrying as much, if not more, weight than the fronts. This was the reason I was so pissed off about having to replace it in the first place... as I'm never likely to tow with mine or load it to the gills in the back.

I've never had ABS on any of the ancient vehicles I've owned before, so can't comment on how exactly that relieves hydraulic pressure to prevent the brakes locking up. But, if the LSV on the Land Cruiser serves the same purpose as ones I've had on my old VW vans, then it should be a separate system from the ABS.

But I also stand to be corrected!
 
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stuzbot

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Just for 'The LULZ' as the kids say, I had a look in the workshop manual and, would you believe, it doesn't even tell you which pipe goes where....

SS 2021-08-15 at 11.48.19.png

SS 2021-08-15 at 11.48.39.png

SS 2021-08-15 at 11.48.53.png


And, the LSV itself is equally unhelpful.

Two ports are marked with an F [for Forward?... Front?]. One of the ports on the side and the Bleed Nipple [!!!]. The other side port is marked with an ⬅︎ outwards pointing arrow [which at least has the merit of indicating direction of flow]

20210815_115300.jpg


The port on the top doesn't have any markings at all... unless the one by the Bleed Nipple is supposed to refer to it. In which case why didn't they put it nearer, or on, the port itself? It's a cast piece so they could pretty much make the markings wherever they wanted.

20210815_115318.jpg


Anyway, it's looking decidedly grey and miserable here today. One of those days where it's bound to start raining, the minute I get outside and start getting all my tools together. So I think I'll give myself the day off and return to the fray on Monday.
 

BobMurphy

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So I think I'll give myself the day off and return to the fray on Monday.

According to the radio - today was the "National Day of Leisure", so you're right on message :thumbup: .

Me- I was welding plates into the floor of the '100' :doh:.

Bob.
 

stuzbot

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Hello viewers and welcome to Episode 27 of stuzbot refits his LSV. [film rights still available]

Well, after another nearly full week of life and the weather getting in the way again, I managed to get out today and have a crack at getting my replacement brake lines fitted and the new LSV on. Not much to report. It all went reasonably swimmingly....

Apart from the obligatory Laurel & hardy moment when I refitted the body of the old LSV to hold the various pipes in place at that end, while I manipulated their other ends into place along the chassis rail at the front. Dabbing delicately with my piece of kitchen roll on the join I'd just tightened at the front end and smugly congratulating myself on the lack of leaks, I turned my head and saw a nice puddle of brake fluid dripping out at the old LSV on the back, as I'd forgotten I'd taken the bleed nipple off and not put it back on again. Cue comedy gold as, like the Little Dutch Boy, I lay half under the motor with my thumb over the dribbling bleed nipple port while simultaneously blindly stretching my other arm up into the back and groping round trying to find something to temporarily plug the hole.

Anyway, such diversions aside, I eventually got everything fitted and, much though I wanted to smash that whole area into a million pieces for most of the past couple of weeks, it's always nice to see a shiny new part fitted on your wagon:

20210820_155112.jpg


20210820_155052.jpg


Anyway, I bled up the new LSV and put a bit of pressure in the system by turning the ignition on and pumping the pedal a few times, then checking for leaks. Touch wood. No sign of any so far.

I then fetched the missus for a bit of brake pedal bashing while I bled everything up. Here I have to confess, I diverted from the Gospel According to Toyota. I did have a glance at the manual a while back on the process for bleeding up a braking system with ABS and I remember there was a lot of stuff about pumping the pedal XXX times, turning the ignition off, turning the ignition on, pumping the pedal YYY times, putting your right leg in, your right leg out, doing the hokey-cokey, etc.

I couldn't be arsed with looking all that up again, as it was getting on for dinner time and the missus was wanting to get on with that. So I just did a quick bleeding in the time-honoured fashion of my ancestors for now: pump the pedal til clear fluid comes out the bleed nipple, then hold down pedal while nipple is tightened again. Rinse and repeat a couple of times for good measure". I also only did the back brakes as, any motor built after the flood will have dual circuit braking and nothing's been disconnected further forward than the mid chassis rail.

So here's where it gets a bit 'two steps forward, one back' [which is quite good for me, as I usually end up doing the opposite!].

As I said, no leaks so far. So that's a plus and the brakes are working again. That's yer two steps forward. The one step back is, the brakes seem to be 'turned up to eleven' now. I just rolled back and forth in the carpark at very slow speed, but the brakes were gripping like demons. Absolutely stopping dead with the slightest press of the pedal. So much so, it makes me wonder whether they had been slowly leaking for quite a while before the LSV went, as they are about twice as pokey as they used to be.

All is not completely idyllic though. As I'm getting a 'thunk!' noise when the brakes engage. Almost like they're thumping into place instead of clamping smoothly. I've tried to record it here on my phone, it sounds a bit odd in the recording; a bit deeper than in real life. But should give you a rough idea. Excuse the dull visuals and the phone fumble in the middle. There's also a bit of a squeak sometimes, but that just sounds like yer everyday brake squeak to me. after all the motor has been standing for about 3 weeks, so the brakes will likely be a bit rusty, what with all the rain we've had. ..


So, what might be causing this? Is it because I did an old-timer brake bleed instead of the complex ABS bleeding routine given in the manual? If needs be I'll give it the proper bleeding routine over the weekend. I just wanted to give it a quick sorting tonight before dinner, to see if there were any leaks or anything.
 
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BobMurphy

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Errr - just to be sure . . Where does the pipe with the red sleeve go ??

(Your anti-gravity spring is confusing me - which way up is this thing ?).

Bob (just old and confused).
 

stuzbot

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I followed your previously posted [twice!] photo for the pipes. One with red tape goes to lower chassis rail. The hidden pipe [coming out the top] goes to upper chassis rail and the one without tape goes to the brakes via the rear axle pipe.

The spring isn't gravity defying. It is attached! Just the weird camera angle and torch lighting making it look like it's balancing on its end. The photos are taken lying underneath, looking up at the LSV

EDIT: if you look at the photo from the manual I posted above, that would be taken by someone lying under the truck with their whole body underneath and feet pointing towards the front of the vehicle. I took mine lying behind the truck with just my head and torso underneath and legs sticking out the back. Hence why everything's kind of upside-down and reversed from the manual photo.

DOUBLE EDIT:

Here's the pic from the manual rotated, so it's at the same [ish] orientation as mine:

SS-2021-08-15-at-11.48.39ud.jpg


20210820_155112rot.jpg


I think the 'gravity defying spring' effect is because the picture in the manual is taken with the vehicle raised and the suspension hanging on that side. Hence the spring is extended downwards. With the vehicle on its wheels, the spring is angled upwards....

...at least, that's how my old one was before I removed it. So unless that one was r-e-e-a-a-a-ll-y badly adjusted, the new one is angled the same as the old one was. In fact, I left the old adjuster bracket on the panhard rod in place when fitting the new one; partly to keep the adjustment the same and partly because it was rusted solid and I couldn't be arsed trying to wrestle it off:

Old one, prior to removal
SS-2021-08-21-at-11.24.19.jpg
 
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stuzbot

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Hmmm....

Well, another glorious sunny day here today [not!]. So no crawling about under the wagon for me. However, I went out for a tentative spin round the block before and, as with yesterday, I was getting the clunk noise every time I touched the brakes at very slow speed. But, after a few minutes and getting up to more normal driving speed it seemed to be doing it less and less. So that, after 5 or 10 mins, it was braking quite normally, without any nasty noises.

I'm still occasionally getting a slight kind of 'creak' noise when I release the brake pedal to start moving again from stopped dead [eg. at traffic lights] but it's a lot more 'normal' and familiar sounding to what I've had on vehicles before and more suggestive of slightly seized brakes than the pretty alarming clunk I was getting before.

If it's dry tomorrow, I'll give the brakes another bleed up. Might even do the fronts this time too! But I'm tentatively hoping that I might just have a scenario here whereby the brakes have been a bit sticky through the motor being idle for several weeks, much of which was very wet. I'm also still wondering whether, in addition, the rear brakes have bound up a bit through my suspicion that this LSV area might have been slowly leaking hydraulic pressure for a while now before it finally burst, thus meaning the rear brake pistons have not been going through their full range of motion for quite a while.
 

stuzbot

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Well, given the unending drizzle today, I had to find some indoor [well, front doorstep] entertainment to keep myself occupied. So, as a sop to the collective curiosity, I thought I'd perform some delicate 'angle-grinder surgery' on the old LSV and see just what you get for between £150 and £200....

This is going to hurt you a lot more than it hurts me....
20210821_143131.jpg


The patient's innards revealed. Fancy going to all the trouble of making that piston centre such a pretty colour, knowing that no-one would ever see it!
20210821_143142.jpg


The port neatly dissected here is the one which goes to the brake line on the rear axle [If Bob's diagram is correct!]. I was surprised to see just how little room for movement the piston has. Only a couple of mm.
20210821_143150.jpg


Another view. the port on the right is the one which goes to the feed line [lower chassis rail pipe]. Unfortunately I cut into the piston and wrecked it a bit
20210821_143204.jpg


Casing with piston removed. You can see the piston had quite a collection of O-rings. All of which, unfortunately, I cut through
20210821_143412.jpg


Close up of casing. The hole in the piston cut-out leads to the return port on the top, which goes to the top pipe on the chassis rail
20210821_143430.jpg


The piston. The centre is metal [anodised aluminium?] The outer black piece is plastic and is free to rotate round the central metal core. There were 3 rubber O-rings and a hard plastic one.
20210821_143449.jpg


So, there you go folks. Tune in same time next week, when I'll be showing you how to perform a tonsilectomy, using only an impact wrench and a lump hammer.
 
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