The Triumph Dolomite Club - Discussion Forum

Hi

I have an issue with my 1850 where all 4 brakes are binding and almost locking up then they ease off if i leave it for about half an hour.

From what i have read on the posts i have found on here it is most likely the servo at fault.

(ok when first setting off, then brake pedal high and solid but brakes still stopping fine then all the brakes start to bind) All 4 wheels were warm to the touch after i forced it home for the last quarter of a mile on thursday.

Can someone please confirm if the AEU1304 Sprint servo fits a single line 1850 without having to do any modifications? I think it does from what i have read on other posts.

I want to get the car back on the road as soon as possible and am considering a new servo from rimmers but they dont say the AEU1304 they sell fits an 1850. (1978 model WF742****)

thanks

Alan

All Dolomite servos can fit any model of Dolomite or Toledo, the only difference in the fitment is in the studs, early ones are imperial and later ones are metric. So long as you have the correct nuts (for both sides, body and master cylinder) it's not a problem.

Since buying my Toledo, it has been fitted with the original 1300 servo, a large metric one from a late dual circuit Sprint and now has an imperial one from an early 1850. None required any other mods to make them work fine. I didn't even have to swap to a remote reservoir clutch master to fit the Sprint servo, though access was tight.

I was watching a youtube channel the other night and the guy was complaining to his garage that his year old, $15,000, Ferrari clutch was slipping. Turned out to be a faulty master cylinder, with a little corrosion in the outer end that stopped the piston and pedal fully returning. The same thing could happen to a brake master cylinder. A duff servo is NOT the only possibility! Also check the brake light switch mount bracket isn't bent and holding the pedal down. I've seen this more than once!

Steve

EDIT, last series 1850HLs were actually factory fitted with the Sprint servo. From late 78 on.

Hi Steve

Thank you very much for the confirmation. I read all the posts i could but its nice to have it summed up and confirmed by someone i know has so much experience.

I take your point on the master cylinder and i was thinking of trying the tip i read about loosening the master cylinder to see if that freed it off or it was still locked when the servo wast pushing on the master cylinder. I suppose the action of disconnecting the master cylinder from the servo could free the master cylinder off if it was stuck though.

I will also double check the pedal travel is free, i did try pulling the pedal back with my foot when it happened but not a definitive check.

I don't get much flexibility on how i fix my car as i live on a narrow terraced road and am limited in what i can try myself. At least now i know i can get a servo if i need to take it to the garage.

thanks again

Alan

Apologies to Alan for PMs. Meant to put it on here!

Be aware that the servos (2 ) I have had from Rimmers come with a yoke that fixes the rod to the back of the pedal with a clevis pin.
This yoke will not fit into the back of the pedal. It is shouldered and too wide.
It is threaded (metric?) but as far as I know the originals are welded. So not the easiest to sort.
Why Rimmers have a stock of over 40 of these with no solution is hard to fathom. They had sold 10 before I complained and no one had said anything!!

I am no expert but it would pay to ask. See posts Sprint Brakes ; 10yearsafter.

Cheers
Bob

As Carledo states do not condemn the servo before checking the master cylinder, I've had the brakes lock up in the manner you describe twice, once it was a faulty servo, the other was when the brake master seals started to leak.
When the brakes were applied the pressure was such that the brake fluid leaked past the seals in the master cylinder, the join however between the brake master and servo did not allow the fluid to escape which meant there was no sign of a leak, plus the brake fluid had nowhere to go so the piston in the master cylinder could not return to release the brakes. The car had to be left for the spring pressure to very slowly push the piston back to release the brakes and I only discovered the reason for the brakes locking on when I separated the master cylinder / servo and brake fluid leaked out.

10yearsafter wrote: ↑Tue Mar 15, 2022 7:56 pm
They had sold 10 before I complained and no one had said anything!!

When my single line master cylinder failed, it locked the brakes on but affected the offside front far more than the other three to the point it melted the hub grease!

I have a good used 1850 servo here if it does prove to be that, but I'm minded to think it's more likely to be the MC...

thanks for all the feedback, hopefully it is the master cylinder. I will try some more fault finding when the weather picks up. It has had new seals about 18 months ago. Maybe i should have left it alone, it wasnt leaking its just the old ones were about 30 years old.

When the master cylinder is leaking did that make the pedal firm with no travel? I thought for a few days before they locked up that the rear brakes had just adjusted themselves perfectly and eliminated the pedal travel. Now i know it was just that they were partially on taking up the slack and i hadn't realised.


thanks for the offer xvivalve i will keep that in mind, if im going to spend any money best to keep it within the club sphere as much as possible.