Teves ABS - Project Refurb

Dear All,

After seeing multiple topics related to Teves ABS system, all the hassle that frankly I am unable yo understand - it’s time to kick off bigger project realted to Teves ABS systems installed in XJS model - pre and post lift. An ultimate refurb guide.

From obvious lack of knowledge and limited resources across the Internet - I am certain, I won’t be able to complete this project by myself. I need you all.

We all know how to convert ABS back to vacuum servo, however if somehow the idea doesn’t seems right to you - you are correct. Removal of the ABS may be serious insurance issue or rather void. In case of accident, the chances that you will receive any compensation / your family will after post-mortem equals zero. You may be more lucky if your conversion involves everything including wheel hubs etc… However why do we need that amount of hassle?

Compared to modern ones - Teves is a simple system with only three things in interest: brake accumulator, brake master cylinder and solenoids.

The biggest problem - lack of spares.
We have replacement accumulator sphere made by Bosch that fits perfectly, we don’t have master cylinder seals and replacement solenoids.

I have two Teves III ABS units in good condition. Too good to strip down. I need to purchase something trashed that represents mk3 and mk4 system (unless we have more). Other car makes like Volvo or Saab are also considered. The plan is to strip everything, measure, translate into 3D Cad model and find replacement parts that fits perfectly.

Any parts, any advise, suggestion, facts or fairy tales - are highly appreciated. I’ve got direct importer of Autofren products that promised to find everything if I will be able to measue the original components.

Looking forward to hear a lot!

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Focus on the gaskets and seals. I don’t think the problem is a lack of the metal solenoids/ valve bits themselves, it’s the parts needed to disassemble and reassemble it incase anything gets stuck.

They should also be the easiest bits to produce too.

Perhaps taking apart one of the good units is actually the right thing to do, at least you know that the seals aren’t disintegrated or crushed in there.

Gaskets are not a problem, seals are not a problem if you know dimensions (Autocad pack has access to everything)
The biggest problem seems to be wear on the inner diameter of brake cylinder.

Unfortunately I am unable to find any records/data from manufacturer (ATE) hence the need of physical post-mortem…

If anyone has old/faulty assembly for sale - happy to pay the price.

Teves Mark III?

Lowball him, he accepts offers. (I have no relationship with this seller)

This is Lockheed’s photo I think. It shows what to me is the Teves IV system. Even if I could find a Teves IV manual pedal box (I can’t see why the ‘box’ itself would be any different for LHD vs RHD), I lack the skills to convert my car myself from Teves III to Teves IV. As you say there would be significant insurance complications for a conversion (in the UK) too.

I have a complete spare “master cylinder” & reservoir assembly that has been kept in the shed for years. The condition is unknown apart from me being sure that it is not a “known good, bolt in replacement”. I suppose I’ve kept in on the basis I could possibly rebuild it/get it rebuilt if & when the unit on my car fails. The picture is not my spare it is the only one I can see currently for sale on UK eBay (& the seller is offering free shipping from Poland).

There is a Teves III ABS valve/solenoid block on UK eBay but the seller is asking a ridiculous amount of money for it. There was so little interest in these things several years ago that the seller left the complete master cylinder/valve block/reservoir attached to the manual pedal box I bought for very little money.

If you are able to get anywhere with this project it will be very interesting for all the XJS owners who ‘need’ to try & keep functional the Teves III ABS on their cars.


Thanks for detailed answer.
Teves Mk4 looks like typical, modern construction. As beyond my experience - why everyone’s complaining onnits reliability???

If you are referring to the Teves IV, I cannot recall hearing anyone ever complaining about its reliability. On the other hand, there are many complaints about the Teves III - including total loss of brakes.

Done, Teves Mk4 (that’s why they call it “IV”) excluded from furher research.

Rubbish Teves III hunt completed. £19 plus delivery:

With good wind and some time, few months of measurements - should have enough data to look for spare parts across the network…

Why bother? I seriously doubt if it’s possible to overcome the Teves III’s fundamental shortcoming, that it’s possible to lose all brakes suddenly and without warning. If you want a project, a much more worthwhile endeavor would be to find or fab brake pedal housings for converting to pre-ABS or Teves IV systems, especially brake pedal housings for M/T cars – having a clutch pedal. Cars not having the Teves III garbage and fitted with a clutch pedal are few and far between, making sourcing such a pedal housing a challenge.


I saw that on U.K. eBay - seller said it had sat for years & was from an XJ40 - which should make no difference AND it was an ideal price that it doesn’t matter if you end up throwing the whole thing in the bin.

I missed out on this on eBay but only because I couldn’t bring myself to pay the shipping charges, a rare item though:





So far I have met three US natives: one from Chicago, other one from Texas and one from Washington. I really like them, but they’re absolutely lacking sense of humour, entirely - even if compared to Mr Bean in UK.
Does it mean that all Yanks are washed away from it???

I am really keen to hear what sort of problems Teves Mk3 can bring, including mentioned uncontrolled loss of brakes, with or without warning…
Converting it back to pre-ABS??? It’s like watching a greyscale TV on your 100" LCD…
I am not bothered with manual brake pedal either (got auto, soorry…). What I am keen to hear is the story of your experience with Teves III. What can fail, why instantly? How?
By the look of it - it’s a standard brake pump with solenoid block…
Also, regardless of the car model I have seen multiple instances of ultra-super-respected workshop knobheads diagnosing brake master cylinder or ABS pump failure, with actual root cause being air in the system.
Also usually - all Teves III problems starts with JagLover trying to fiddle with brake accumulator or attempting to bleed the brakes… And forgetting to top up to the cap…

I may be wrong hence happy to hear all the details (same as the Aston Marting owners, and Ferrari owners as well and…

If one of the front brake hoses blows, you will have no brakes. The Teves III cannot develop pressure in the rear brake circuit unless it can develop pressure in the front brake circuit. Several people on this forum have reported exactly this failure mode.

It should never have been legal for sale in the US. Dual circuit brake system have been required for decades to prevent any total loss of brakes. The Teves III has two circuits, but one depends on the other to work. I suspect that had NHTSA noticed, it would have been banned.

For me, I wouldn’t have one in my car. You may object to non-ABS brakes, but the pre-ABS system in the XJ-S was far safer than the Teves III. And I’m still driving non-ABS Japanese cars, one of which I had to deliberately decline an option in order to avoid having ABS.


That makes sense, however it also makes sense…

Teves III is a dual circuit system at least on the paper, it went into many cars, even those most expensive.

Out of all these vehicles, there is one deserving for ‘special’ status in terms of abuse, lack of service and designed with inboard rear brake calipers that will last forever even if fillled with pure water… Hmm, forgot what wad the name of it… BBQ or WTF… BLM maybe… Ahhh! XJS yes, XJS…

Shortly I’ll do post-mortem, it will be easy to reveal if system is dual… Fingers crossed :wink:

So far, ATE (aka Alfred Teves) is still making stuff for JDM market. Hard to believe they’ve released that sort of shit globally…

Here, staring from post no. 6

The how and why

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That’s an excellent source of information, however from attached section drawings it looks exactly like modern dual circuit system. It also shows the reservoir tank precisely higher in front circuit - apart from the fact that the tank has multiple sections, each fed with brake fluid independently and independently drained when hose burst occur.

So, unless one of the valves fails - system should be operational if burst happens…?

If a front hose blows, you cannot develop any pressure in the front circuit. Thanks to the way the master cylinder functions, that means you cannot develop any pressure in the rear circuit, either. It doesn’t leak, it just doesn’t work.


We have two pistons there, both are pressed at the same time. When pressed, both are sealed tight between the circuits. The front valve is closed (no fluid return) when pressed, while the other piston passes the magic hole allowing the booster liquid to go into rear circuit…

Even if the front section drains - the pressure from accumulator hits the rear brakes… It’s not about pressure in front circuit, but position of the piston moving into clearance with the hole leading to rear calipers.

Am I wrong???

Note that, even in the Teves III instructions, it points out that if the pump isn’t running, you will have no rear brakes. The rear brakes cannot be actuated by the piston. They can only be actuated by pressure.

So to summarise:
If front brake hose bursts and we have no pressure left in accumulator - then really creepy ride begins?

If we look at the section below, it looks like piston movement is a trigger - while moving towards it opens the valve to accumulator and creates clearance with rear brake circuit…???

You might still have pressure in the accumulator, at least for a while. You just won’t have any pressure in the rear brake circuit.