Technical 1993 Type 290 Brake Servo

[bugsymike]

If vacuum holds for a fair amount of time, that indicates servo good , however vacuum pump could still be not as good as it was in 1993 shall we say.
Just a point when brakes gave cause for concern was the pedal hard but not stopping or did it travel a fair bit and still not stop?
If more pedal travel then possibly a weak brake master cylinder.
To be honest I could give you a whole list of things vehicles can have problems with after working on them since 1969.
Old brake fluid with high water content boiling if not changed in the last few years, brake pads deteriorating, even pistons seized in the brake calipers so only one working, I have had that on older Iveco Daily's.

 

[Stevetyphoon]

When the incidents happened, the brake pedal was solid, barely any movement at all until hand brake on revved up a bit and then pedal went down, then all good.
Recent MOT no advisories on the brakes. I even told them about the issue but they passed the van.

 

[bugsymike]

So it does seem to indicate a lack of servo assistance.
Possibly a weak vacuum pump unless you were coasting in neutral.
I have never had to test or had an issue with those vacuum pumps, mostly on Iveco Daily's even with 200k miles, but in fairness most were not very old maybe 10-12 years at most, not like 1993
It may be possible to put a vacuum gauge on the pipe, but I am not sure what the measurements of a good one are.
If the issue only happened after repeated braking on a long hill, maybe an extra vacuum reservoir, but I would be guessing?
I assume yours is a manual gearbox and you were using engine braking by changing down etc?
With the same type vacuum pump on that engine in my Iveco Daily's 3.5 tonne and towing 3.5 tonne, I didn't hang around and never had an issue like that in the 2.5s and 2.8s.
Out of interest have you ever put your vehicle on the weighbridge as many campers are seriously over the limit a lot of the time, where as commercial working vans often are only up to limit half of the life.

 

[Stevetyphoon]

So it does seem to indicate a lack of servo assistance.
Possibly a weak vacuum pump unless you were coasting in neutral.
I have never had to test or had an issue with those vacuum pumps, mostly on Iveco Daily's even with 200k miles, but in fairness most were not very old maybe 10-12 years at most, not like 1993
It may be possible to put a vacuum gauge on the pipe, but I am not sure what the measurements of a good one are.
If the issue only happened after repeated braking on a long hill, maybe an extra vacuum reservoir, but I would be guessing?
I assume yours is a manual gearbox and you were using engine braking by changing down etc?
With the same type vacuum pump on that engine in my Iveco Daily's 3.5 tonne and towing 3.5 tonne, I didn't hang around and never had an issue like that in the 2.5s and 2.8s.
Out of interest have you ever put your vehicle on the weighbridge as many campers are seriously over the limit a lot of the time, where as commercial working vans often are only up to limit half of the life.

I have changed my driving habits...used to do removals around Europe pre-Brexit with a 2007 Mk7 Transit, often likely pushing or over 3.5Te. Never had a brake issue.
After Sunday's episode on a steep slope into Budleigh Salterton beach car park, I should have just stopped and waited for the lady to reverse the 75m and then drive down the hill in 1st, rather than slowly follow her down just using my brakes.
I can get round it if drive with the brake problem in mind but it shouldn't be like that....but maybe it's just a weakness.
Our Hymer 534. is pretty much the smallest model. I should put her on the weighbridge but likely to be only 3.2Te.

 

[bugsymike]

I have changed my driving habits...used to do removals around Europe pre-Brexit with a 2007 Mk7 Transit, often likely pushing or over 3.5Te. Never had a brake issue.
After Sunday's episode on a steep slope into Budleigh Salterton beach car park, I should have just stopped and waited for the lady to reverse the 75m and then drive down the hill in 1st, rather than slowly follow her down just using my brakes.
I can get round it if drive with the brake problem in mind but it shouldn't be like that....but maybe it's just a weakness.
Our Hymer 534. is pretty much the smallest model. I should put her on the weighbridge but likely to be only 3.2Te.

Sounds like it could have been a bit more dangerous if you were not an experience driver.

 

[Stevetyphoon]

Hi Mike, hope all is well with you.
I have been doing some tests - increasingly longer lengths of time from switching off the engine to pumping the brakes and have come to the conclusion that the servo does not hold any vacuum for longer than an hour.
What I am worried about is if the servo is not holding a vacuum for long now, it surely will get worse and the braking deteriorates further.
I am thinking that due to no issues picked up during the MOT that the fault lies with the servo. Would you say that is a fair assumption?
If so, do you know of anywhere or recommend anyone I can get a secondhand or even a reconned servo?
Cheers
Steve

 

[bugsymike]

Hi Mike, hope all is well with you.
I have been doing some tests - increasingly longer lengths of time from switching off the engine to pumping the brakes and have come to the conclusion that the servo does not hold any vacuum for longer than an hour.
What I am worried about is if the servo is not holding a vacuum for long now, it surely will get worse and the braking deteriorates further.
I am thinking that due to no issues picked up during the MOT that the fault lies with the servo. Would you say that is a fair assumption?
If so, do you know of anywhere or recommend anyone I can get a secondhand or even a reconned servo?
Cheers
Steve

You may be worrying unduly re turbo holding vacuum, some are better than others. Try comparing with another make of vehicle.The ones I mentioned that held vacuum the next day were not common.
If you cannot hear any leaks / hissing with engine off it is probably adequate.
My concern is more of vacuum pump is not providing enough vacuum when engine is running.
I doubt if any parts available to recon modern servo units these days.
In the old days Girling made a brake servo that was mounted under the bonnet away from the master cylinder so had hydraulic pipes,seals vacuum rubber diaphragm, etc in a service kit which I have fitted. These days it is a throw away society.